SJohn, I have not been following your sitch, but I just want to say that I have been where you are many times, that the disgust at their behavior gets so intense that you feel like even if they wanted to come back, you don't want them anymore. I have walked through that fire many times, but when I give it to God, He always reminds me that it's of course not possible for me to want him anymore, only God can make that possible for me when the time is right. I think that the secular version of that would be that true detachment means letting her go but keeping your heart in a place of forgiveness for the sake of your kids watching your example.
When my H even talks about taking my kids for one night, I feel like I am going to die of terror and horror. In my case, I would be concerned that he would not actually take care of them, certainly not emotionally. But I totally understand how you feel, the absurdity if having your kids ripped from you when it's not you who wants to dismantle anything. It feels so unfair and so violating. I keep standing but I totally understand what you are feeling; you are a loving father and they are lucky to have you! My H is in home but hasn't had a relationship with our kids or provided even an apple for them in 5 or 6 years. And he says it's my fault for that too. Your W doesn't know what she is doing or saying right now. A day will come when she will realize the damage she has done.
I believe I will see the bounty of the Lord in the land of the living. Wait for the Lord with courage. Be stouthearted, and wait for the Lord.