There is absolutely every reason to believe that once you make your mind up, it is made up for good, Zenchaser. I was in a bad romantic relationship a long time ago, and I broke that off for good, not for a month or three. I was DONE. There was nothing left there for me anymore.
If alcohol is like that for you, you can do it for now, for next month, for good. You can make a forever decision about this. I liked the idea of doing it for the present moment - I will never now drink - because it is only in the present moment when we can act, when we have power, when we have control over our actions.
You most certainly can succeed, and I think you will. I believe in you, Zenchaser. Onward!