Hi and welcome to SR, bertwash. Sorry for the situation you are in that brings you here.
Rambling is fine. It really does help to get our stories out of our heads to begin to make some sense of it all.
You ask if she is an alcoholic, and I don't have a response to that. She may be and she certainly acts like it with the out of control drinking. The once-she-starts-katy-bar-the-door behavior. But ultimately it boils down to her drinking if affecting you and your marriage. I would recommend some Al-Anon meetings and some reading up on alcoholism and the family. And continue to post here and read the stickies at the top of this forum's home page.
And remember - you didn't cause her drinking, you can't control it, and you can't cure it. Setting rules may seem like a good idea but its a band aid on a gunshot wound. For her to stop drinking, she needs to make that decision herself, for her own reasons. Sounds like she isn't quite ready for that just yet.
Take care of yourself. It's all you really have control over anyway.
~T