My partner of 8 years started having an affair with her sponsor's girlfriend while I was away visiting my terminally ill mother for what would be the last time I saw her alive. This was after I stayed with said partner during her "bottoming out" period (she had an affair with a 52-year old male morphine addict on food stamps who had no voice box due to cancer) but optimist that I am, I let her stay and attempted to "work through it"—and then she discovered AA (although I had bought her every alternative recovery program's book on the face of the planet.)
Then, the secrecy and hushed phone conversations about the program began. And the phone calls from her sponsees (all of whom relapsed within three weeks of working with her), who would interrupt my writing time with demands about why didn't I know where she was and when would she be back and they were outside a bar and needed her goddammit!! (Or other various epithets and obscenities—apparently some of them weren't aware she was gay and/or had a long-term partner.) (We were professional academics—she was at conferences or the library or her writing carrel, I was working from home and being constantly interrupted by these codependent nutters.)
End game: She left me for her sponsor's girlfriend, breaking up two couples one month to the day after my mother died. Before doing so, she commented: "I'm afraid your grief over your mother's death is going to threaten my sobriety." (Although she knew my mother and my Mom never expressed anything but acceptance and love toward her.)
These are craven, sociopathic narcissists who have found the perfect place in which they can justify their cruel and immoral behavior, replace their choice to use alcohol irresponsibly with their addiction to AA meetings and anyone outside the fold can go to hell, no matter what they may have put that person through or how much that person may have endured to support them.
Oh, and by the way—she now works for the Department of Homeland Security.