
So in chapter 41 when we found out kato went to an orgy party and he says he didn’t cheat on him… this was in the way beginning when they were living together but weren’t dating but he was still saying he loves him?

It's been a while since I read this manga but if I remember well, Kato was still very immature at the time and struggling with his feelings and desire for a man who was constantly rejecting him. Iwaki wouldn't give him the time of day and Kato, who then apologized about it I think, did admit that it was a stupid thing to do. He was young and dumb, hot blooded and used to people finding him irresistible so he got carried away imo
In the last chapter of this season the uke ups and leaves him without telling and pretty much says have a good life so for those complaining about no revenge/redemption arc hopefully this satisfies you