Advice?

So I stayed with my boyfriend after I found out he cheated. Our baby was six months old when I found out. It's been months and he hasn't shown any interest at all emotionally or sexually. I find the idea of sex with him repulsive now. I told him I don't think things are working and we should separate , he said no?? That I'm being selfish and should think of the baby. That we'll work on things but it seems like he actually doesn't want to work on things...

Any advice?