So often I hear in recovery rooms, "It is what it is." And I think you are coming to that hard realization. Your husband is deep in active addiction, he is draining the family of vital resources, he is posing a threat to your child's safety (we cannot underestimate the lengths an addict will go to to feed his addiction while he has solo care of a child), he has destroyed the non-negotiable ingredient of trust in the marriage, and he has not made any serious attempts to get clean. It is what it is.
You are the sober adult and the caretaker of an innocent child whose highest good is in your hands alone. So you have to do what must be done, based on what is true today in your life.
Living separately, getting a legal agreement for continued financial support, and finding a counselor to help you through the hard times ahead seems the most realistic action to take right now. Continuing the status quo would be making choices based on hopes and dreams and you just cannot afford to do that, as a responsible mother.
No one knows if he will find recovery. But you can create a home which is a safe and sacred sanctuary--no drugs addicts allowed--while you wait for more guidance and more to be revealed.