Is being informed about your drinking something she needs to know or is it something that you need to tell her. I think you should be clear about your motives here; you should not burden someone else with your baggage. And, what will you do if her response is not what you hope it to be? In my opinion, there are many possible outcomes from this meeting, few of them good. Can you postpone until you have a few months of sobriety under your belt?