You're doing the right thing. Do not argue or defend yourself, you know it does no good.
Go as dark as you can as he's still spewing. Saying, sorry you feel that way, when he starts, and then that you have to go will keep you from having to listen to it.
Do not contact for any reason other than financial or about the kids. Stay on subject and don't veer off to a R talk. Protect yourself from his spew.
