So he cheated on me with this chick and we are poly. And he wants to be with her and me. I’m so angry and upset and I feel even more upset that he’s pressing the issue now, right after I found out. I’m angry that he cheated and he thinks that there is a way to stay with me and her. And to add to the conundrum, he’s basically beat it into my head that she’s better than me and better suited for him then me. But when i try to leave, then he is apologetic. How do I deal with this??

If he cheated on you, that’s a problem…but what sticks out to me is this part where he “beat it into your head” that she is “better than you.” That is abuse. That is abusive behavior. And this thing where he is apologetic when you try to leave? Part of the classic cycle of abuse. You deal with this by leaving the relationship. He is not healthy for you to be dating. Run.