It sounds to me.. your W may be starting to feel guilty about not taking a larger and more parenting role in this decision with you, or she could be feeling guilty about her past decisions and is now trying to take it out on you. My advice would be to remain as up-beat as you can, as short as you can with W (execpt for the issues on your children), tell her the kids are going to stay with you and she can come see them or talk to them whenever she wants. If she becomes angry or irate, tell her you will talk to her when the two of you can discuss things calmly and hang up. At some point she will realize that "the grass is not as green on the other side."(at least thats what Im hopeing in my situation) Hand in there man Beleive me I know it's rough. But on the bright side you do still have your kids. Take that and use it for the strenght and courage you need to get through this. You will make it. Keep your head and keep writing.
