marie1960 is so right--it will be much easier to wait and marry later if he stays sober than it will to marry now and divorce later if he doesn't.
Probably the biggest thing I'm learning from Alanon is to WAIT when I'm not sure what action to take. Time almost always shows me what I need to do. And sometimes time resolves the whole problem w/o any input from me at all (imagine that! the world turns w/o me pushing it!).