Why do people hang out with people they don't like?

I just learnt one of my friends doesn't like me, or basically anyone in our friend group besides his boyfriend and its left me wondering like, why is he even hanging out with us?
I do have a history with him from accouple years ago, he did some nasty stuff to my best friend however they became friends again and so I became friends with him again as well. He DOESNT like my best friend either (even though he became friends with her again???) and tried to stop his friends from speaking to us but it somehow worked out that I joined the friend group.

like man if you literally just outright said you didnt like me bc of the shit which happened (WHICH WAS YOUR FAULT.) I wouldn't have became friends with you again man.