I was speaking with my A's daughter today, about my A and some of the issues that have developed over time with him and relationships, and had a moment of clarity regarding my situation...
While in a relationship with an A, the alcohol is usually the main problem at the time when it is happening, but the alcohol rarely comes by itself, and is actually usually caused by something else. Since alcoholism is a genetic disease, which means that a person could be an alcoholic without ever having taken a single sip (and hence never know - like a bipolar person who never hits a time in their life stressful enough to flip the switch and turn the bipolar disease "on"), there is something that makes the drinking happen and turns the alcoholic into a drunk.
In my A's case, he can't stand the world at large, is insecure in relationships (the closer he feels to someone the more he has to monopolize their time), he internalizes things that weren't meant to be personal, and he has difficulty being close to more than one person at a time (which means that single person is getting 100% of his attention, and expected to give 100% of theirs back).
If he can't work through these problems, he cannot have a healthy relationship with anyone, and so in reality then yes, the relationship is doomed to failure and I cannot be a part of it. If he's willing to work through it, I am willing to work through it with him.
...I just realized it sounds like I'm saying he's 100% to blame - I'm not perfect either. I wouldn't have stayed this long before throwing him out (he's in inpatient rehab right now, first time ever) if I also didn't have emotional baggage to carry around. Some of it I brought with me and some of it he trained me, and all of it I need to work through before I can have a healthy relationship with anyone, as well.
So in short, there's a lot of things going on in a relationship, because while alcohol is the most obvious problem it's not the underlying one (although it is the one that needs to be fixed first). Without fixing both people IN the relationship so that they are whole again... it's hard to have a fulfilling relationship with partial people who are not confident in their own individuality.