I am so sorry. I am guessing you are older (going by your parent's marriage term). I also had no experience with addiction and found out my BF had an alcohol history after 4 years. I do love him and have stuck by him through a couple relapses. But he is a kind, loving person who is successful and normally treats me like gold. I feel he is worth it. Having said that, though I am over 60 and actually still pretty desirable -- after this one, I am done. My daughter can't understand why I don't just go find some "great" guy. I happen to think mine is a great guy but nevertheless -- if something goes South with this one -- I do not plan to get in another relationship. I will try to fill up my need to be a helper type by making this world a better place in another way. I will help build community gardens, work at Habitat, help elect good reps -- you know the drill. Maybe even join an Intentional Community.
Don't be so hard on yourself -- it is really, really hard for nice women to find a suitable companion after a certain age. Any man over 50 that I would even consider dating (and have dated) left me for a woman in her thirties. It just seems to be biology. I love my guy, but even he is a pain in the ass. Women seem to think we are failures if we aren't "with" someone.
I know this sounds easy to say -- but my recommendation to you is just to swear off men for awhile. Get your own life in order, save some money, help small lost children -- find something that brings you passion beyond helping addicts who most probably have a personality disorder. Read up on Narcissism, Anti-Social, and Borderline Personality Disorder. Lately, my favorite read is Emotional Intelligence and Social Intelligence -- a real eye opener. Many alcoholics are just dealing with a disease process that once dealt with reveals a great worthwhile human being. But some addicts are simply too emotionally damaged to rescue. Don't waste your precious time.