I know it hurts and I'm sorry you are left trying to 'figure' out the why's of any addicts behavior. When I'm in active addiction I have no idea why I do what I do. So it would be impossible for anyone that isn't an addict to understand.
You dodged a bullet. You can thank him when he finally shows up. Do yourself a favor, find someone who isn't an addict. Unfortunately most of us are a real pain in the backside.