Depressed 33weeks now.

I'm a ftm at 33weeks, I've been with my partner for 4years. When I first found out I was pregnant he was cheating on me. Long story short I think about it all the time. It puts me in a funk. I feel like he blames me and it my fault. Idk why I do I just feel like it my fault. Can I get tips on how to not forget but too move on and not talk about it with him? When I bring up the girl name he gets soooo mad. But inside my heart is still broken so it hard for me to not bring her up.

Thanks ladies