How to deal with a breakup during pregnancy?

My husband and I have been going through serious relationship problems lately. I had to find out he is seeing someone else. It has completely ruined my trust for him. Im expecting our second child and he just up and left me. Im so sad and depressed, and would do anything to feel better. I can barely eat, or sleep or think. Im so confused and all i do is cry every few hrs. I been eating only once a day, my appetite is ruined. I would never leave him like this and i cant understand how he could do this to me After ten years. He always tries to come bak when we have problems. But as bad as i want to be with him i dont think this is healthy. I really wonder when the sadness will b over. Someone please give me advice on how to handle this. Im 32 wks pregnant and very confused. How do i begin to feel better?