He is angry because he is extremely unhappy and it's much easier to blame you for it than himself. (It's called 'blame shifting' and they're famous for it). That would require taking responsibility for his actions and choices. He clearly is not working an AA program, I don't care how many meetings he's attending!
Why are you taking his abusive phone calls? He's not sending support. He's not talking to the children. What on earth do you have to talk about? When you stop being his whipping post he might just have to turn that rage where it belongs.