First of all, I'm the recoverying alcoholic in my family (sober for 10 months). Also, I'm the wife. And I've been through 2 divorces. I have 4 kids. (Just a little background for your frame of reference.)
My biggest piece of advice is to not leave the house and move elsewhere even temporarily. That would give your wife the right to file for full custody based on disertion. I've seen it successfully done. Even though the spouse moving out was just doing so to get some head space. The other spouse got full custody almost immediately.
Before you make any moves, see a lawyer.
You are being brave and honest and forthright. Your wife may attempt to turn your words against you, twist what you say, manipulate you into doing things you don't want to do, etc. Be as gentle as you can with her while you protect your rights as a father.
It doesn't matter what a great mother she is when she's sober, like ToughChoices said. She's not sober. So you should not trust her to take care of the kids.
And I want to reiterate, when I read your post, I thought, "Here is a man who is mature, thoughtful, sensitive, caring and a good dad." You deserve to live your life and to be happy. That is not a malicious thing. It's is a good thing. You're kids will be better for it.