Hurtmom, So sorry you went from such a good day to a bad one. That's the roller coaster ride with these WAS! The one thing that struck me is statement that breaking up with OW "will put ME over the edge." That and the fact he's pretty much doing what he wants, when he wants to do it ... he's thinking all about himself. He's being pretty selfish. What does he think this is doing to you?
You keep going down those cheeseless tunnels with him. Think about what you've done in the past few months that has helped and what has not. Is there anything you can do differently?