No, leaving in many states with the kids would not be allowed and in my state would be seen as putting the kids in the middle. If he wants custody, he has to want and show that he has the children's best interests in mind.
I think he's doing just fine. Lost your head a little, but I don't blame you one bit. Detach, get a life and pretend as if she is not there. Detach, did I say that? LOL. It's doing you and the kids no good at all being emotionally volatile. From now on, she's a ghost. You don't see her, you don't hear her, unless she knocks some dishes off the shelf. Then you call in an exorcist. Just focus on the kids, focus on yourself, focus on your lives together. Do family things together, play games, take them out, ask them what they want to do. Have fun and above all, detach.