To be brief would you let someone move in with you who has cut all contact with his family, has no friends, been married 3 times and your DC hate?
I have a friend going down this path and am so worried for her. I've met this man a few times and everything about him screams danger.
She is gradually being alienated from her own family and friends but thinks everyone else is the issue.
I'm not sure I can do anything but keep a watchful eye. Given the opportunity I am sure he would coerce her to cut me off too 