Hi, and welcome.
The thing to remember is that you HAVE tried to help her. When I left my second husband, who went back to drinking after a near-death experience directly related to his drinking (liver shut down; talk of transplant), I still cared about him. I realized, however, that if anyone was going to save his life it had to be him. I had done all I could. I was not up for repeated deathbed vigils. I imagined myself placing him in the hands of his own Higher Power (which wasn't me), prayed for him, and walked away with no regrets. It was entirely out of my hands.
Alcoholics are very good at blaming others for not "standing by" them as they spiral down on their path of self-destruction. Don't let it get to you. You HAVE stood by her. You HAVE tried to help. You are not God.
If you've been married only four years, you are not going to be burdened with much alimony, if any. Is she disabled (apart from her drinking)? Just because she chooses not to support herself doesn't mean the court will continue to indulge that. Sometimes "rehabilitative" alimony is ordered to give a spouse time to get on her/his feet. But that isn't indefinite, and as I said, with only four years of marriage it might not be a factor at all.
You'll know more once you talk to a lawyer.
Glad you're here--stick around, and keep going to Al-Anon. It was a lifeline for me.