You were the girlfriend of a fairly famous singer, the problem is that for some time now he has been behaving too self-centered and narcissistic, that is obviously not to your liking and you simply can't stand it anymore.

Katsuki: We always fight because of you, idiot! I don't know how I could be with someone like you. He says arrogantly, and in a way those words increased his pride, thinking that you will put up with his attitude...