For those getting NTR vibes, IT does happen with the senpai, they get drunk sex, and causes a big drama with the wife, becomes a major plot point later on or THE plot point. Also apparently they change genders back after having sex, he turns back to male after with the senpai, gets some with the wife and turns back into a girl, thats why the wife learned about it. After that the wife and MC have some distance for quite a bit of time, wife tries to understand about trans and sjw shinanigans, and grows to understand it, she even has some lesbo sex with some girl and encounters a crossdressing dude who was the co-worker of the mc. The girl in the convenient store used to be a dude too, he died from a sports accident, wants to return back and wants mc to turn her back, but never went sexual. that girl finds some way to turn into a dude but ending wise she reverts back to a girl and ends up i assume dating her other co-worker. Ending wise, both parties learn to forgive and understand their relationship better and get back as a couple. MC decides to somewhat have the child instead of wife for some reason and thats how it ends. Happy ending, with cheating as the major turn around plotpoint of the story. The cheating stopped after the sex btw so it only happens that one time, both mc and senpai feels bad about it because they both cheated on their wives. It happens very early on, id say 1-2 chapters more ahead, and the rest fleshing out how they will come to better understand their relationship and their future. IMO the wife getting to understand stuff dragged a little bit, but i do like the ending.