WOW...Have I heard this before.
Okay you are with a man who for some crazy reason treats you like crap but YOU know he is the right one. Sadly addiction is one of those things where the symptoms are so varied. You need to understand that until he decides to change there is NOTHING, ZIP, ZERO, NADA you can do to help him.
Many family members/significant others of addicts etc just wish they could help. In fact they are working to enable the person to find deeper and deeper bottoms. It is like a family member who has a broken leg and you keep feeding them pain pills without actually FIXING the leg.
So, you love them. Yeah, but do you LOVE them enough to hold the pistol while they blow their brains out? Because that is essentially what enabling does. Alanon offers you some options. But the most important thing you need to learn is that YOU are not responsible for their behavior, their decisions or their actions. What you need to decide is how far you are willing to help them dig the hole of pain and self abuse before you discover you have been helping them dig their own grave.
Look this is tough, I do not disagree, its brutal. I have had to turn away in pain as a friend makes another rough decision. But I know I would rather them discover "gravity" and skin a knee than go on to jump off a building.
Finally...SO you are 31, Good Lord you are still young...but the question you have to ask is, "Are you staying with him because you want to or because you HAVE to?"