In the same way as each alcoholic has only so many relapses in them before they leave ( this earth), perhaps an alcoholics partner has limits too.
In any case it is extremely tough living with untreated alcoholism, whether the alcoholic is dry or drinking.
Mester, this happens a lot. It is not you so much as the effects of this illness. We don't always see it because to us our ways of thinking and doing are normal, why would anyone have a problem. But I will never forget the look on my fathers face when he saw I had relapsed. Such sadness and disappointment. He never said but I know it just tore him up.
Alcohol was my solution to life. While my alcoholism was untreated I could stay sober for spells. I never really had a good spell doing that but some people do. Then something bad happens, like wife leaving, and the most natural thing to do is to turn to the old solution, the only one we know. It is different if you find a new solution.
My wife left me in 2007. She is never coming back because she died. It never occurred to me to drink because I have a new solution and drinking is no longer necessary. Instead I got on with my responsibilities, looked after the children and the people who depend on me. I could do that because I had The Power. Not my power, but The Power, who has seen me through all the low spots so far.
Whether you wife comes back or not is irrelevant to your recovery. You can recover regardless of anyone, provided you want to and are willing to do whatever it takes, and that will be more than just not drinking.