Perhaps it would help to think about how the baby feels about you. I don't say that to make you feel worse. What I'm saying is that the child will love it's mother when it's born and depend on you. It's helpless and alone in the world without you and would feel abandoned at various points in it's life if you were to give up now.

I'm sorry you have to be involved with someone who doesn't live responsibly. But don't let that pass on as something you should blame yourself for. A cheating spouse is just that, a cheat. You haven't done anything to deserve that. You've been betrayed. No wonder you feel depressed.

Hollywood glamorizes betrayal as something to be passed off as no big deal, but in real life it causes a lot of hurt and pain. Don't give up or feel like you, or the baby, have anything to do with what's taking place in his mind. He is failing as man, father, and human being. Let him live with it.