Steve,
You don't have to tell her how bad it really is, at least not right now. Just tell her you know it's a problem and you want things to be different. I spill my guts because I've never been able to do it before. Just like you I've been so ashamed of myself and my actions that I clammed up about everything & guess what? That just made me drink even more. It may get worse than where I've been, I've only spent a few days in jail because of drinking, but I really don't want to sink any lower. TRULY wanting to change, not just half-assin' it is what is the difference for me this time. Believe me, if you were to take a poll of my friends & family & ask theem who is the worse drunk they ever saw, I'd be #1 on every list. That just motivates me more to make sure I show everyone that even the worse alcoholic they've ever seen can get his life back on track.
You can do it. If you start craving a drink, make a deal with yourself: Put on some tennis shoes and go for a brisk walk for 30 minutes or an hour. Tell yourself if you still want a drink when you get back you can have one. My bet is you will not. Don't give up.