To the people saying the purple guy cheated. DUDE the story started with him trying to break up and getting killed. In this universe he killed the black guy in self defense. I dont see anything wrong with the purple guy trying to get with the girl when HE WANTED TO BREAK UP but that abusive murderer would kill him literally.
PEOPLE DONT OWE LOYALTY TO ABUSERS ESPECIALLY WHEN THEY CLEARLY SAY THEY WANT TO BREAK UP
people defending the black haired guy have either never got into a relationship or they are themselves the abusive ones and it shows. when people want to break up, YOU BREAK UP, there's no other way around, you can try convincing and stuff but forcing them is never an answer, ITS NOT EVEN A RELATIONSHIP AT THAT POINT. if someone forces you to stay with them, it should be clear that you dont owe your loyalty
Threesomes or love triangles with two ukes? I'm tired of the multiple top tropes
https://www.mangago.me/read-manga/we_want_to_service_idolish7_dj/
Other than this I can tell you a few with uke-seke-seme if you're interested
either author was going through a breakup while writing this or he just made our MC a mentally ill guy
I think it is the latter ╥﹏╥