Change thd locks and go into plan B.
If he is serious about changing, which is a long shot, he can talk to your IM.
Your children are adults if I understand that right. Don't tell them to have contact with their father if he i really such a toxic person, let them decide for themselves.

Maybe you can contact Steve Harley if dou have counseled with him, to ask for his opinion. And read the article on this website "when to call it quits".

me, DH
all the children