In my situation, AH's personality disorder and alcoholism were intricately woven together. He was diagnosed with something called "co-morbidity." Ultimately, the DSM-IV diagnosis showed that he had something called schizoidal personality disorder. Basically, this disorder manifests itself by isolating oneself, retreating into a fantasy world, and not having any particular meaningful attachments to people. It's not the same as schizophrenia, but the similarity is that people with AH's type of personality disorder don't have much of a personality - kinda like "flat-liners" as I call them.
Thus, the alcohol alleviated the lack of personality and he took on a "personality" when he drank. Other than that, he was pretty much detached and had no clue as to how normal relationships should function. When I realized he'd be out beyond Pluto whether he was drunk or sober, I realized it was time for me to cut my losses.
I think some marital issues would be there whether there was alcoholism as a factor or not. We all have distinct personalities and ways of doing things. A successful marriage to me is about being adept at the art of endless negotiation and the ability to laugh at oneself. Those factors aren't present when one is mired down in addiction. However, there are plenty of folks who don't drink and still don't have a clue how to negotiate differences in a marriage.