Welcome to Sober Recovery. I am so sorry you are going through this.
You have come to a very good place to seek help. There are so many people that have walked in your shoes here. We get through this kind of confusion and pain together.
Start by reading the stickies at the top of the forum. There is very helpful advice there.
In my opinion he has abandoned you and your baby. I would seek legal advice and get a court order for support. This is a terribly selfish disease and that is exactly what you are experiencing.
He is right about al-anon though. Most of us work our own program and let our loved one's work on their sobriety. Al-anon is a great place to get help.
Please keep reading and posting. This forum has helped so many of find a path back to sanity.
Peace,
Hanna