Escorts & dating sex sites??

I'm 28 & 1/2 weeks pregnant with my first baby (boy) & have just found out my boyfriend has been on dating sites sex sites and searching up escorts. I don't know what to do I spoke to him about it we had a argument last weekend because he blocked me on some social media sites & I wondered why & he said he was angry so signed up to a site and paid from our joint account to be on there so I would see it to spite me. I said ok didn't want to argue but then in the afternoon I see he's been on more sites and searching escorts & messaging them before we even fell out. He says he's never met anyone and never got a reply but how can I trust him?? He's signed up to loads of different sites. He says he sorry and he was stupid but I'm so hurt I have anxiety and depression it's making me so I'll ;( heartbroken