He will be an addict all his life, it's just a matter of whether he is active or not. This is a disease that has no cure.
If you cannot leave him, then be prepared for the ride of your life.
Have you been to meetings? Lots of people there who are going through and have been through what you are experiencing, some have decided to stay with their mates, others have cut the cord, but are still in recovery from codependence. You might want to start your recovery, whether he is or not.
Keep posting, we are here for you.