"I never saw a wild thing sorry for itself. A bird will fall frozen dead from a bough without ever having felt sorry for itself." D. H. Lawrence
If you're done, file on Monday. Sounds as though her leaving may be good for your health and sanity.
But where does she think she's taking your children?
As you work with your attorney (find the Godzilla of divorce lawyers and hire her/him) make sure you get how custody - legal and residential, temporary and permanent work in your jurisdiction.
Your STBX sounds as though she is pretty effed up. That needs to be her problem and neither your children's nor your issue.
Her: WW/57 Me: BS/63 24yrs M
3 great kids, now 22, 20, 17 b,b,g
D-Day 8/14/08, D 1/13/11