Hello Panda
I would think, going by his behaviours with his previous partners, he has had serious issues for quite some time.
As Dee stated, he showed you who he was from the start. The chances of him changing are minimal, unless he truly wants recovery.
I believe you would do well to concentrate on you, and your life, and leave him to his own path. I certainly wouldn't choose to go down that path with him. It would not make for a happy life.
If you don't want the contact with him, which I think is wise, block any way he can contact you. If he shows up at your home, call the police.
Much Love
Bute x