29 weeks and contemplating divorce

I've been with my husband ten years total, seven married. We've has or trials and tribulations like every marriage (I've been cheated on several times). We have tried to work on things but they always end up right back where we are. I've never cheated or wanted revenge except for wanting to punch all parties involved square in the throat. We currently have a 20 month old and I'm 29 weeks pregnant. Every time my husband gets freaked out by something happening in his life her runs back to his side chick. We were doing so well for so long and once again he went running back to his whore. I don't have any excuses for staying except my daughters, in all honesty it terrifies me to think about doing it alone. We haven't had sex in months because I for sure as shit am not trying to catch anything. He doesn't get it and I'm just fine going over it. I just feel so lost.