If you haven't already, please take a moment to read the sticky "What Addicts Do". It sounds exaggerated when you first read it, but it could not be more true. Maybe it will help you understand how little control you have over what he does, which will take some of the burden off you.
You are not responsible for his behavior and can't control it. What I hate to see you do is try to figure out what is going through the mind of an addict. I've done that and it can drive you to the brink of insanity.
Please do what it takes to be safe and please keep posting.