From what I understand in the game, the MC gave permission for one sister to do this to the other to get her used to it, because in the future they would want the three of them together, so he wasn't betrayed by anyone
But he was, because (had to check the thread for her name because its been a while) Emilia didn't know the MC approved of this, but she still went along with it while in a relationship with MC, so she cheated.
I mean, you can give it a pass if you like lesbian stuff thats ok, but if a girl that is in a relationship with MC gets intimate with another person, without MC having told her he was ok with it, then that means that girl is a cheater, as simple as that. If mc is a retard and gets excited about his girl being willing to cheat on him when it is with another girl, then thats his problem, but it doesnt mean he isnt getting cheated on, that just means he is a cuck.
And btw,I am talking about how the scene was portrayed initially, in the version I played, I know the scene had some changes so maybe now Emilia gets permission or is informed beforehand that MC is ok with it, and if that is the case then she would not be cheating ANYMORE, but in the original version, she was and she was enjoying every second of it.
Plus I dont think it is avoidable which was the original question of the other dude. And the "it is to get the three of them together" is just an excuse, it wasnt necessary to have this lesbian scene, mc knows he can have a harem and they would have agreed to it. what does them fucking change, nothing. It is just a scene to appeal to those with a lesbian fetish and that was initially developed in very bad taste at the time, being borderline ntr (dev admitted that he missed the mark with it and thus he changed it).
So what you said might be true now, but I was talking about the scene pre rework where Emilia was happily willing to cheat on MC and the other girl was more into fucking her than in the supposed "plan" to get the three together it felt more like an excuse for her to get into Emilia's pants and having her way with her.
here found the comment of the dev saying he changed it.
I slightly misrepresented the vibe and meaning of the scene at that time.
Now this scene looks a little different.
And checking the thread now I remember this scene happened early in development, talking years ago, and it just left such a bad taste in my mouth that couldnt get into this game after it.