Really, I agree with Cynical One and OutToLunch (per usual!). He was an addict long before I got involved with him, and after I learned of the depths of his problems (after about 3-4 months of dating) I chose to stay. I chose to accept his behavior. I chose to accept settling for being treated as second-best, or as a convenience. I chose to accept being the counselor, social worker, chauffeur and prison warden.
Although I still have no regrets, because I learned a lot during that period in my life. I have clarity now that I don't think I would ever have grasped had I not gone through it with him. This clarity lends itself nicely to other life situations and helps me remember that I can only control myself and my own actions/reactions to life.
Fortunately I escaped pretty much unscathed....not emotionally unscathed, of course, but I didn't have any lasting damage to my financial future, no kids together, no shared property, etc. So I consider myself pretty damn lucky.