My late ex mother-in-law gave my ex father-in-law an ultimatum regarding his drinking. He stopped and although he didn't use a program, he never drank again. Their marriage seemed happy to me.
I gave the same ultimatum to my exah in fall of '08 after I 'hit the wall' and couldn't stand his drinking anymore. He moved out in order to continue drinking and we divorced a few months later.
Although al-anon is opposed to ultimatums, they let you know where you stand.