First, I hope you were tested for STD's.....
Your baby isn't due until March. He has told you he isn't interested in working on his addiction. I see no reason to have contact with him at all, not by phone, texting or coming to the house. Your not married any longer so he has no reason to be there. Take steps to take care of yourself and your children because as you said, you can not count on him for help.
No contact will give him time to do one of two things, realize what he is losing and get help or continue drinking himself into oblivion. Over the next few months, allow him to deal with himself and you take care of you and your kids and that little one on the way.
He made his mess, let him deal with it alone.