Fiance said he feels like he fucked up his life

We've been together 10 years have 2 children. About 5 years ago we broke up for 2 months and slept with other people which hurt both of us. Hes not over it still .He regrets ever even meeting me but still loves our children. He told me tonight that he has been putting on a happy face everyday and that every time hes been nice to me was just him acting. I try my hardest to be the best person I can every single day. I cook , I clean, i take care of our child all while I'm currently pregnant. We havent had sex in a while because I'm just not confident while I'm pregnant so that's bothering him too. I dont know what to do. I know hes not going to leave me or kick me out of our house so I guess I'll just be stuck here forever all while he pretends to even like me. This really sucks.

Edit: I wont move out and he wouldn't ask me to move out because we both couldn't be away from our child at all.