It's not exactly the same for both, but I think healing of a relationship is most likely when both partners are seriously working on recovery. I think if I had stayed involved with Al-Anon it might have made a difference in my first marriage. I left him, basically because I was feeling (I thought) "stuck" in the relationship. It's complicated, and looking at my part in that whole thing is something I have to do in my recovery now. I think my attitude at the time was, well, he's sober, he's a good guy, nothin' wrong with me, now. I think maybe if I had actually WORKED the Steps at that time, I might have had my head screwed on a lot straighter.
Amazingly, I was actually resentful of how "good" he was. I used to think that my family and everyone else liked him better than they did me. And maybe they did, I know I was so wrapped up in myself (budding alcoholic that I was, though I seldom drank during my marriage to him) that I wasn't that pleasant to be around--not that great a friend or family member.
As I said, this is something I am going to have to face, and own, in my own recovery. Having been an alcoholic AND the frustrated partner of two of them, neither role is a day at the beach.