As a former substance abuse counselor, I can recommend that you investigate some twelve-step programs: Alanon (for those affected by another's addiction,) Adult Children of Alcoholics (for those affected by family dysfunction of any kind,) and Codependents Anonymous (for those struggling with issues of codependency.)
It is my suggestion that you try out one or two of these programs. They all have telephone meetings. Peruse the websites and see if you can relate to any of the literature. Check out the phone meetings and give them a fair shake.
The twelve-step philosophy is not for everyone but it has helped an enormous amount of people. It is a self-help program and is considered spiritual in that it's useful to consider that there is a higher power outside of oneself.
There are a lot of misconceptions about the twelve-step programs. I suggest you try it for yourself.
In the end, it doesn't help to understand your partner's issues. The way we move forward is to understand our own.