My Girlfriend Cheated on Me With a Senior, so I’m Cheating on Her With His Girlfriend Chapter 8


Infiltrating a girls-only meeting

TL: Furby

ED: Danny

I contacted Karen immediately after my call with Touko-senpai.

Naturally, it was with the end of arranging to meet with Karen the next day.

“I couldn’t stop thinking about how depressed you were, Karen, so I cancelled my previous appointment with my friend.”

After I said that, Karen was apparently extremely happy about having been given priority since she continued to scream ‘I’m so happy!’ over the phone multiple times.

During the next day’s date too, for the first time in a long time, Karen was affable towards me.

She clung tightly onto me. It had been a while since we had walked holding hands too.

I decided that we should go to the school festival. We showed ourselves at the refreshment stand from our group, and though my day on duty was tomorrow, I decided to help them out a bit. This was because I wanted to ask the guys of our group what they knew about Kamokura.

It seemed that Kamokura had shown up at the refreshment stand a little before we did and had been looking for people who’d play Mahjong with him. However, finding out that there was no one here who would play with him, he took his leave. He must have a surplus of time on his hands now that his so anticipated trip with Touko-senpai fell through. Served him right.

One week after that, Karen continued to stick close to me in the same way as when we had started dating. Everyday she wanted to eat lunch together with me too. And at the school cafeteria to boot. 

She was most likely thinking of showing off to Kamokura how well she was getting along with me in hopes of making him get jealous. On my part, it would be more comfortable and fun for me to eat together with Ishida and my other friends from the faculty, so she was being a big nuisance.

During this time, Touko-senpai and I hadn’t met in person either. 

This was because there was no indication of Karen and Kamokura meeting with each other. Nonetheless, we did keep in contact with each other every day.

Personally, I thought of Karen’s current attitude as nothing more than her way of getting back at Kamokura. That was why I surmised that given enough time, sooner or later she would again have her affairs with Kamokura.

I wanted to know Touko-senpai’s opinion on that matter, so I asked her.

“Certainly, Isshiki-kun, the possibility of it happening like you think exists.”

Touko-senpai spoke in the same manner as always.

“I thought as much. That’s why I was thinking to check when the two of them seemed most likely to go back to their love affairs.”

The moment I answered, Touko-senpai voiced a different opinion as if to stop my reasoning.

“However, isn’t the opposite also possible?”

“The opposite?”

“Yes, the possibility that Karen-san reflected on all that has happened, and she came to the realization that you are the most important person to her?”

“You think it could?”

“Looked at from a distance, the two of you presently look like a couple in pretty good terms with each other.”

“That’s because both Karen and I are acting the parts for it. Weren’t you the one who told me to do as much, Touko-senpai?”

“That may be so, but I just want you to think it over one more time. If you truly think that hurting your girlfriend and breaking up with her is the correct thing to do.”

… What was she saying now that we were so down the road? Hadn’t we already resolved ourselves to make our cheating partners taste despair and regret so strong that they’d want to be dead?…

A thought then crossed my mind.

… Could it be that Touko-senpai is thinking of making up with Kamokura? Could Kamokura have had a change of heart and corrected his ways, and now Touko-senpai is noticing that?…

I was assailed by uneasiness.

“What do you mean by that? Does that mean that you are changing your mind in that way, Touko-senpai?”

“No, I’m not. It’s just that, if Karen’s attitude towards you changes, it’s only natural for your feelings to change too, right? I was thinking that in that case, it would be better for you to think over once again what the best option for you would be. After all, if you were to continue on with the rest of the plan like this and break up with Karen, there would be no going back.”

“We have already come to a point of no return. From the moment that Karen cheated on me! It’s already impossible for me to go back and date Karen like before. Even now I’m forcing myself to meet with her for the sake of our plan.”

I cut my words for a moment and then proceeded to speak the next line with strength.

“Also, there’s no doubt that Karen will cheat on me again.”

I then heard Touko-senpai heave a long sigh from the other side of the phone.

“If you’re so strongly resolute about it, then it’s fine. I won’t say any more. I didn’t have any intention to make up with Tetsuya from the start either. Let’s continue according to our original plan. All in preparation for the D-day.”

“Yes, I look forward to it too. So, what do we do next?”

“I believe that Karen-san’s feelings should be focused back on you for the most part by now, Isshiki-kun. First and foremost, you have to keep it that way.”

“Understood. However, I get the feeling that Karen turning her feelings back to me is nothing more than her way of getting back at Kamokura-senpai. I believe that once they go back to cheating on us, we’ll be back to square one again.”

“That’s why we need one more push right now.”

“What would that push be?”

“I told you before, didn’t I? Raising your popularity among the girls.”

She had indeed told me about that before. That said, I had not the slightest idea as to what I should do for that.

“And how exactly do I go about doing that? I can’t even imagine how I’m going to get started with that.”

“Right. I see you have been properly keeping your word about what I said before. But that’s not enough. That’s why I’ll create an opportunity for you.”

“What will you do?”

“I’ll gather some girls I know, including those from our group, in the next opportunity I have. As for the pretext… I think I’ll go for something like, a chance for us to talk about Christmas, New Year’s, Valentine’s and other winter events.”

“Uh huh.”

“You, Isshiki-kun, will then pretend to pass by that place by chance. I will then get you to join the girls’ circle there and raise your popularity among them.”

“Will it really go so smoothly? I have this image that the moment a man intrudes into a conversation between girls he’ll be hated by every one of them.”

“I’ll lead them into accepting you by saying something beforehand, like, I want to know a man’s opinion too. By doing that, if you happened to casually pass by, it wouldn’t be unnatural even if you joined our conversation, right?”

“I guess in that case it wouldn’t. But I don’t have anything to talk about that could be well-received by girls.”

“Hm, then investigate all you can about the applications I’m going to tell you. Smartphone camera applications for taking selfies.”

Touko-senpai gave me the names of a few different camera applications used to take selfies.

“The advantages and disadvantages of each of these applications; whether they’re free or paid; what kind of special functions they possess. So long as you can explain each of these to the girls in an easy-to-understand way, I believe that should give you a fair amount of points with them.”

“I see.”

She was right. Women seemed to be particularly careful with the photos they uploaded on social media or messages.

I could bet they would love to know all they could about applications that let them take cuter photos, even if only slightly.

“Once you have the mood going for you, try making your appeal by saying that you’re good at programming. It is a fact that we are studying Computer Science, and you also told me before that you can work quite well with Java and Python, no?”

I had said that indeed. The reason being that, if I were to mention something which could put me even a bit closer to the level of Touko-senpai, the sophomore with the best grades in the Computer Science major, that was about all I had available to me.

“You know how even arts and humanities are including programming classes in their curriculum? Well, there are many girls that are having serious difficulties with the assignments in those classes. Up to now, those girls have been asking me for help and I’ve been creating programs for them. I’d like to have you do that in my place. I believe that doing that should raise your reputation among girls considerably. In that way, you’ll be able to interact with other girls consistently too.”

Makes sense. If it’s only that, I should be able to do that much at least.

“Your reputation with the girls isn’t bad in the first place, Isshiki-kun. There were a few girls I know that said you were quite the ‘cute-looking attractive guy’ from the time you first started attending the university.”


I felt my face inadvertently turn into a grin.

“Really. I don’t think that Karen-san would’ve chosen you as her dating partner if that weren’t the case.”

I didn’t understand very well how girls gave their assessments, but if Touko-senpai was telling me that, I’m certain it was true. It was at this time that a certain problem came to mind.

“However, isn’t that plan inconvenient for us?”


“That would be because it would be known to other people that Touko-senpai and I are hanging out together. Once that happens, wouldn’t it be only a matter of time before Karen or Kamokura-senpai get wind of it?”

Touko-senpai, however, answered seemingly unworriedly.

“I’ve already thought about that part. I’ll have Kazumi call you over. You just have to act out that you and I are simply a senpai and kouhai who went to the same high school and know each other.”

Ooh, as you’d expect from Touko-senpai! She’d already taken that into account.

“Keep your attitude towards me the same as the one you’ve had with me in our group all this time. Don’t talk too much with me in particular and instead focus on making conversation with the other girls. I too will act as if I didn’t have too much interest in you.”

After that, Touko-senpai and I discussed various other things, such as the approximate time and date in which we would effectuate this plan, what other topics I should bring up to talk with the other girls, which store would be the best to make it seem it was by chance that we met up, etc.

Concerning the effectuation of our plan, it was left in that she’d contact me after she had determined all the girls who would be gathering.

Together with that, she would be telling me everything that she knew about the personalities, interests, and the things that each of the girls who would take part hated. 

Having that information, I would think about what topics each of the girls would like and which would be best I evaded.

At first, I had thought that it was impossible to do something like raise my opinion among all the girls, but listening to Touko-senpai, I started to think it could actually be unexpectedly simple to achieve. Not to mention that Touko-senpai herself will be helping me at the same time she was part of the group of girls. Perhaps it was only natural for this to be simple then?

Afterwards… Karen and Kamoku’s cheating continued.

It started on Thursday around one week and a half from the day that the cheating love trip plan went down the drain. 

Honestly, they didn’t learn, or maybe I should say they were salacious.

The next week, I was walking in the opposite direction of the train station that I usually used.

Across the university and the station, there was a shop which had an all-you-can-eat sweets on the opposite side of the road. Touko-senpai and the other girls were discussing among themselves what they would do during the winter events of our group.

We were on the last third of November. We had many long-awaited and important winter events awaiting us in the near future. To name a few, Christmas, the New Year, and Valentine’s.

The group to which we belonged planned every year events that went together with those dates.

They had gathered under the pretext of collecting all of the girl’s requests in respect to those events.

My character in this was that of a single man who happened to come to eat a cake.

I ordered a beverage and a cake on the first floor and went up to the second floor with the two of them.

Despite it being a weekday during daytime, the store was considerably full.

… First thing is searching for where Touko-senpai and the girls are seated. I have to get closer to them for this…

With that in mind, I was about to walk towards the inside when someone called out to me.

“Oh, is that you, Isshiki-kun?”

I turned to look and saw Kazumi-san waving a hand at me from behind a pillar. Touko-san and four young women from our group were together with her.

With the tray still in my hands, I got closer to the table seats where they were.

“Isshiki-kun, you alone?”

Kazumi-san asked me in a most natural way. Just like we had planned.

“Yes, I’m alone.”

“If you’d like, sit here with us.”

Kazumi pointed to the seat beside her.

“Thank you. I’ll accept your invitation then.”

I pulled over the free chair closest to me and sat at the same table as them.

The people at the table were, excluding Touko-senpai and Kazumi-san, 4 girls from our group. From the Economics Department, there were the sophomore, Mina-san, and the freshman, Ayaka-san; from the department of Literature, there was Manami-san, who was a sophomore too; and last we had a freshman from Business School, Yuri-san.

All four of them were girls who held clout within our group. I expected nothing less from Touko-senpai. She didn’t overlook a single thing when choosing the members for this reunion.

Mina-san, the sophomore from Economics, was the first to inquire with me.

“How do you and Kazumi know each other, Isshiki-kun? After all, Kazumi isn’t even in the same group as all of us.”

Kazumi-san answered that question faster than I could.

“I knew him by name and face because of Touko first. Then, a little while back, I was looking for a programming book at the library and he helped me out. I’ve been asking him for help with my programming homework every now and then after that.”

“Oh! Is that so? Still, Kazumi, I ask that you don’t make a move on a freshman from our group as an outsider. Isshiki-kun is a rookie we have high expectations for!”

Mina-san laughed after saying that.

“I’ll be joining your group soon after this, so there won’t be any problems then, right?”

Kazumi-san too laughed as she retorted. She sure was someone quick to make a comeback.

“But you know, Isshiki-kun is already going out with Karen. You’re already too late.”

The one to say that was the sophomore who belonged to the same Literature Department as Karen, Manami-san.

“Yes, she is late.”

I deceived her with a slightly vague answer.

“Mitsumoto Karen, huh. You know, I don’t really like her. Though she does seem to be popular among the guys.”

Mina-san spoke bluntly.

“Hey, Mina! You shouldn’t say those things in front of Isshiki-kun!”

Though Manami-san’s words showed a will to stop her friend, she herself too was smiling and laughing.

“Aah, you’re right. Isshiki-kun, I’m sorry. You see, regardless of how you see me, I’m the type to say out loud what I’m thinking. Please don’t think too much about it.”

Ayaka-san, the freshman from the Economics Department, was the next to speak.

“Still, I have to say that I agree with what Mina-san said. Karen… Her attitude changes a lot depending on whether there are boys or not around.”

“Right, right! That time during the summer camping event was horrible too, right? I was honestly sickened by that.”

The one who gave that same opinion was the freshman from Business School, Yuri-san. 

I had already been told beforehand by Touko-senpai that the opinion of the girls in our group about Karen was bad.

So, the line that I should say here was…

“Well, I am Karen’s boyfriend, so I believe in her. She’s a girl with a good heart deep down.”

I covered my story with that. According to Touko-senpai, if the other girls started to bad-mouth my girlfriend, I should always cover for her. That was the one thing that I had no need to agree with them on.

The group of four girls looked at each other’s faces for an instant.

“R-right. It must be because Karen has good things that Isshiki-kun is dating her.”

“Truth be told, Karen is cute. She even has this fluffy air about her.”

“Seen from a boy’s perspective, she may be the type they can’t bring themselves to leave alone. Don’t worry too much about what we said.”

Nonetheless, Mina-san was the only one who didn’t leave the topic without adding one last stinging sentence.

“But still, you should be more careful about who you choose to date.”

I too wanted to completely erase my having dated Karen from my past.

Saying that she was a good girl at heart nearly made me puke.

I wanted to speak my heart out and reveal to all of them that Karen was a woman who was rotted down to her personality.

However, Touko-senpai had already warned me that girls think that men who speak badly of their own girlfriends as the worst, so I was to make sure that under no circumstances I did so, even agreeing with them if they belittled her.

Still… I had already known about Touko-senpai before, but the other girl’s opinion of Karen really was noticeably bad. I may have been quite shocked were it not for the love affair thing.

“Aa~ah! I look so ugly in this photo I took just now!”

Kazumi-san yelled as she looked at her smartphone. She was trying to change the topic of conversation for me.

At the same time, this was also the signal for me to lead the conversation towards the selfie applications.

“How so? Could I ask you to show me?”

Not missing a beat, I spoke to Kazumi-san.

“Look! I took it at this store a few moments ago. But don’t I look somewhat ugly here?”

She appeared normal in it in actuality, but because this was an act we were putting on, I didn’t mention it.

“I see. It may be the fault of the illumination. In which case, if you adjust the level of balance between the color of your skin and the whiteness…”

I fiddled with Kazumi’s phone as I was saying that.

“Ooh, it now looks so pretty! That’s Isshiki-kun for you! No way I could upload it if it didn’t look at least as good as this!”

Kazumi-san said that exaggeratedly.

“Isshiki-kun, do you know about camera applications?”

The one who took the bite first was, as you could imagine, Mina-san. The other three girls were all staring at me with interest too.

“I’m not too deeply knowledgeable, but I have thought of maybe designing one of my own. I have therefore investigated a bit about them.”

That was true. I had once tried making a camera application in Android thinking that I could maybe earn some extra money. Though it seemed that in order to ‘make it look cuter or make it look prettier’ you needed a certain amount of know-how about the operation, so the small application I created didn’t end up selling well.

“Oh, then! Which application of those available right now would you recommend?”

The one who leaned forward was Yuri-san. 

“K app was the most famous one until a while back if I’m not mistaken. But now other applications like SO app, UL app, BP app, and B9 app have garnered a lot of popularity for themselves, no? If you want to focus on raw photos, it would be SO. If instead you want to process and manipulate the image a little more, perhaps UL or BP would be better.”
(TL Note: There’s a limit to how much you can play with copyrights, no? Each app is a reference to real Japanese camera applications: SO references SODA, UL is Ulike, BP is BeautyPlus, B9 is B612. I also think K is カメラ360)

(ED/N: IDK anything except B612 )

“I’m using UL for now, but there are so many different functions that I don’t know which I should use for what.”

Manami-san was the one to say that.

“I imagine the most important thing is the look of your skin, so in the case of UL…”

Like that, I continued to explain to the group of girls the features and recommended usages and points of the selfie applications for a while. I also added a bit of talk about some image processing techniques that could be used according to the situation.

The source for all this information was what Touko-senpai had told me before. The things I researched only went as far as a little about the most popular selfie camera applications at present and about some paid services they had.

Especially the processing techniques, there was no way I could know about them. This itself was something that Touko-senpai herself had learned from her model friends, and I was simply repeating them.

I must say, this had a far better reception among the girls than I had thought. On the inside, though, I was dying from the nerves of whether I had blundered, and they had seen through our lies…

Ayaka-san spoke in admiration.

“You’re incredible, Isshiki-kun. To think you even know about this!”

In Addition to that, Kazumi-san nodded in a manner which expressed her total agreement.

“Isshiki-kun, it’s no wonder you’re majoring in Computer Science, you know so much about applications and programs! I’m always getting saved by him in my programming assignments, you know?”

No, the one getting saved all the time is me without a doubt… I made a bitter smile in my mind as I thought that.

This woman was really good at reading the atmosphere and covering for others.

“In that case, could you teach me too next time? I’m also having some serious problems with my programming homework.”

Mina-san said that and leaned over toward me even more.

“Then me too! I have programming classes starting next semester, and I’ve been worrying about it non-stop. Isshiki-kun, could I ask for your help?”

That was the freshman of Business, Yuri-san.

“I want to ask for your help too. I don’t know left from right when it comes to programming, so I was wondering what I’d do.”

Now it was the freshman from Economics, Ayaka-san, who spoke.

That was when Touko-senpai spoke for the first time.

“You’d be doing me a great favor if you can help them with their programming assignments, Isshiki-kun. I have some classes that are keeping me very busy this semester, so I also have a considerable amount of work to do myself.”

She spoke curtly.

Since the moment I sat at this place, Touko-senpai had almost never turned to look my way.

It was an attitude that screamed that she had not the slightest interest in me.

With this, there shouldn’t be anyone here who would possibly think that Touko-senpai and I were in a truce.

“We had been relying completely on Touko all this time after all. For what it’s worth, I did feel bad about taking your time when you were busy.”

That was Mina-san again.

Manami-san then added on.

“But if we can also rely on Isshiki-kun for help, that means your burden will lighten, right, Touko?”

I too answered amicably. It was my best chance to make an appeal out of my one and only strong point.

“If you are fine with me, you can call on me whenever you want. If it’s something like general programming lessons, then those won’t be much of a burden for me.”

“Yay! Isshiki-kun, thank you!”

“Isshiki-kun is so knowledgeable about camera applications too. Aah, I should’ve gotten acquainted and closer to you sooner!”

“I thought the same too! If this is how you were, I would’ve liked talking with you about many things from the start!”

“It’s such a shame letting Karen monopolize you all this time.”

“You shouldn’t be saying that out loud!”

I patted my chest in relief. It would seem that I somehow managed to succeed at this strategy to raise my popularity at the girls’ meeting.

Touko-senpai then looked at her wristwatch on her left arm and made a gesture of brushing it twice.

It was the signal for me to take my leave.

According to Touko-senpai, knowing when to leave a conversation with a girl is of crucial importance.

Apparently, leaving when the girls are thinking something similar to ‘I think I want to talk a little longer’ is the best timing.

On the other hand, remaining seated in place for the whole time makes them think that you’re annoying.

“Well then, I’ll be leaving now.”

I got up from my seat while saying that.

“Eh, you’re leaving already?”

“You don’t need to hurry so much to leave.”

I answered despondently to the girls who called me with those words.

“I have a promise to meet with a friend. And I also want to buy a book for one of my classes before that.”

That was my answer, which of course, was a lie.

“I see. That’s a shame.”

“Let’s talk again with more time then.”

“See you in the group!”

“Goodbye! Ah, I look forward to your help with the programming assignments!”

I made a slight bow to the girls as they said that and left the place.

With this, I should have completed everything nicely, just as Touko-senpai had told me.

I would call her later to ask her about the results.

“Today was a great display.”

Night came and as soon as I called Touko-senpai’s phone, the first words which came from her were those.

“After you left, we remained there alone and continued to talk for a bit, but everyone’s assessment of you was quite favorable.”

“Thank you very much. However, this was all thanks to you, Touko-senpai.”

I was happy to be praised but being before the very person who laid the ground for me to achieve that, it wasn’t in me to take pride in that.

“There’s no such thing. Carrying out what I said down to the letter, along with your conversation which was on point and your natural smile. It was those things combined which led to every of the girls in that place having a high opinion of you. It’s more than enough for you to hold your head high.”

Oh man, being told stuff like this by Touko-senpai made me feel quite abashed. 

“Moreover, your way to cover for Karen was perfect. You didn’t agree with their opinions and not only covered for your girlfriend, but also did so in a decent number of words, not being overly obstinate in doing so.”

Hmm, that too was because Touko-senpai had already told me that during the times I spoke with girls, I had to pay special attention to my replies and take care not to speak too much myself.

Then again, I was bad at talking with people I didn’t know, and doubly so when they were women.

“With that, we can say that the whole group of girls there are now practically your allies. That’s why we can now say that the moment that Karen-san’s cheating is revealed, she’ll get isolated and hated by everyone. They’ll think, ‘How could she betray her boyfriend, who so kindly covered for her!?’.”

“That’s something to be grateful for. It was a considerably big matter for us whether we could get the girls to side with us, after all.”

That was a worry I had had for a while now.

I do believe that dumping our partners in the worst possible manner when they were most in love with us was the best way to get our revenge, but I was scared about having the people around us feel compassion for them, thinking that it was too horrible, that we went too far.

Kamokura had stolen the girlfriend of his kouhai, so I couldn’t imagine him having too many guys who’d sympathize with him.

However, I didn’t know about the girls. I didn’t think there’d be girls who’d endorse what Karen did, but I had heard that women are beings that have a high level of empathy. It may have been possible for some girls to start thinking, ‘There was no need to go that far, was there? Poor Karen, being subjected to that’, after seeing Karen cry.

And if a girl who’d defend Karen appeared, the damage she’d get from the revenge plan would get halved or worse. 

If possible, I wanted to teach Karen and Kamokura a lesson so painful they would never forget it.

“True. I do believe that the majority of girls will side with us. Still, I do have a small idea about it. Let’s discuss it next time.”

She was thinking about even that? Well, there shouldn’t be any problems if I left it to Touko-senpai, though.

Nonetheless, I did feel like, as a man, I needed to have some active role myself.

“See you, then.”

“Ah, please wait a moment.”

Just as Touko-senpai was about to end the call, I hurriedly called out to her.

“What is it?”

“Well, it’s about the homework I had from before… Actually, I have a small favor to ask.”


“Yes. The one where I had to write the report on the ‘conditions that make up a cute girl’ anew.”

“Did you manage to arrive at a conclusion?”

Touko-senpai’s voice got excited. It was a voice which was slightly expectant.

“I already have an answer inside of me. However, I can’t exactly put it into words properly yet…”

She awaited my next words without speaking.

“And it’s for that, Touko-senpai, that I would like to ask if you could date me for one day.”

“Eh? Dating me?”

In a seldom seen sight, Touko-senpai asked back in a surprised voice.

“Yes. I think that ‘cuteness’ differs depending on the person. That was why last time, I ended up saying only things that covered the general notion. This next time, I don’t want to do that, but instead, I want the answer to my homework to describe a ‘cuteness’ which matches you perfectly, Touko-senpai.”

I was very serious about this. The answer to which all my thinking about it since back led to was this.

Touko-senpai didn’t speak for a long time. I could tell that, from the other side of the phone, she was wavering, uncertain about it.

“Please, I beg you. If even with this I were to say something which you consider to be off the mark, senpai, you can go ahead and lose all hope in me at that instant, I won’t argue with you.”

Even with that, Touko-senpai remained reticent for a while.

However, before long, a single word came from the other side of the phone.

“… Ok…”

“Thank you very much!”

Unintentionally, my voice got livelier.

“So, when should we go on this date?”

“I’m fine whenever. So long as it suits you, Touko-senpai.”

“Got it. Then, how’s next Sunday? I have that whole day free, after all.”

“That’s an O.K. for me! Well then, I look forward to next Sunday. I’ll contact you later for the time. I’ll be the one to think about what places we’ll visit and other activities!”

“Yeah, I understand. Well then, see you next Sunday…”

She said that and hung up the phone.

Good, with this, all preparations were in place. All that was left now was effectuating the plan I had come up with.

I had to make Touko-senpai accept me and become the partner with whom she’ll be at the last moment of our revenge!

I had renewed my resolve.