Advice much needed - Long I'm sorry

He lived with me for about seven months last year, which put a strain on our relationship. Around the end of October, he left the house saying he'd be back in thirty minutes. I stayed up all night waiting for him and he never came home. Around ten the next morning I got a phone call from a man who said my boyfriend had ran off with his wife. I immediately broke down and didn't know what to do. We went looking for them and couldn't find them. Me and her husband became friends and found comfort in each other because we were both going through pretty much the same thing. After a few weeks he committed suicide and I blame his wife and my boyfriend. A week after that, I got sent to a mental hospital for a month or so for trying to commit. 

After I got out, me and my boyfriend started talking, and we decided to try again. I was happy again, and I did everything in my power not to think of what he did. Now I'm pregnant with his child and don't know what to do. I feel nothing, I'm not excited. I'm not particularly happy. I feel so stupid and angry. Even though it's my fault. But he on the other hand, is so excited. He constantly has his hand on my belly and always smiles at me and says "you're having my baby. My baby is having my baby." 

The past few weeks I've been thinking about what would be best. As much as I want to stay with him, I constantly worry. I don't know what to do.