Sheesh! What is she? Three years old? You may recall the Latin phrase "in vino veritas" - I think that in anger that certain truths are also said. Sometimes they are also ones that we wish we could take back. In her case, she's told you that she's not going to sign anything and she's not going to let you go of her free will.
I do worry that if she were to up the battle that she might try to weaponize the kids. She is being selfish and doesn't have the same sort of support structure around her that you do that says that is a truly bad idea.
I think you should start working under the assumption that she's not going to sign any darned thing any time soon and you need to do what is best for you and your children. What that may be, I don't know.
At one time I had a vision of dropping all of my STBX's stuff off in OM's driveway with divorce papers on top of it and a note "She's your problem now"
On BD H52, W50 T27, M26 S21, D23 BD-9-Mar-16 D-15-Jan-18 Final-19-Apr-18 I am a storyteller. The story may do you no good. But a story is never for the listener. It is always for the one who tells