Feeling like my relationship is ending.

I need to vent and need some advice. I'm inna 3 year relationship with my partner and at this point our relationship is holding on my a thread. For context, I found out over a month ago that my partner cheated on me, he asked another girl for nudes because we were in a "rough spot" in our relationship and to make matters worse it was a month after I found out I was pregnant with baby number 2 and tells me I need to tell him how to fix our relationship, to me if he made the conscious decision to ask a girl for nudes over a small rough spot, theres nothing to fix nor would it or should it be my responsibility to find ways to fix a relationship i didnt put on the line ..Since then I feel practically nothing in our relationship anymore, my trust for him has diminished into nothing and my body practically shrivels at his touch. This is a man I love alliteration all my heart. Anytime I tell him I'm uncomfortable with him doing something like touching my boobs or smacking my ass, if I don't have a reason to be uncomfortable with it, he'll say he doesn't see an issue with him doing it and because he's securely frustrated he'll do it. I don't recognize this man anymore. Why can't good things last anymore.