I didn't mean to like your post. Sorry. Sometimes it's better to not put all the effort in just to keep it going. It hurts. But you can't keep hanging on if he's not going to try as well. Can you try marriage therapy before the baby comes? Or have a little baby moon to spend time together before deciding its over? When things are tough, I ask myself "am I better WITH my husband? Or WITHOUT him." If you can answer that question to yourself truthfully you might have a better idea of what's best for you and the relationship.
I'm sorry you're going through such a hard time right now.