Idk what to do

So my bf asked to login to his Instagram on my phone and didn’t logout so I went through his dms and he had messages from his ex one said “you look good damn” and another that said “I wish we could have worked things out” i don’t know what to do I’m 32 weeks pregnant with our twins and I love him more than anything other than my babies and god but I feel so betrayed! I feel like I can’t trust him!! I have even asked him not to follow her and he unfollowed her for a while and followed her back! He also just lost his best friend to suicide so that’s some of the convo!! Here is part of the messages