My grandfather was an alcoholic and took Cocaine and speed when he was a member of parliament to be able to write speeches and stay up for long periods at a time. (Funny, I was also a Cocaine addict and an alcoholic). My grandmother pushed him to stop for years and he did - after twenty years. He stopped the Cocaine after he retired as a politician and they were happy together for their remaining years together.
My uncle was an alcoholic and suffered from sexual addiction as well. His wife tried to push him to stop, but never got anywhere with him. She then detached from him, started doing her own things, got herself a job, made her own friends, started a travel group. They started living together again when my uncle started AA. They are still together, just bought a new house and their relationship is based on mutual respect and a deep loving friendship.
My great-grandfather was an alcoholic and had the worst sexual addiction I have heard of. He had about 19 children with 13 different women a part from his wife and mistress. After my great-grandmother died, he stayed loyal to his mistress and had a bunch of kids with her as well, but late in life he stopped drinking and they had a good relationship afterwards.