I haven't chimed in because to be honest I'm not sure what to make of this situation. It kind of sounds to me, based on what you've posted, that the two of you have simply grown apart. The fact that she ran into a problem with alcohol and pills doesn't necessarily make her an alcoholic, or her behavior "dry drunk." Not everyone who abuses alcohol or medications is an addict. She's changed, and you want her back the way she used to be. Maybe that isn't her any more. I know I've changed quite a bit from the way I was when I was younger. I don't like all of the same things, my opinions about things have changed, the way I relate to other people has changed. I found that, in my first marriage, I became unhappy. It wasn't because my husband wasn't a good guy--he was. The relationship just felt "wrong." We did some marriage counseling, seemed to make some progress, but the bottom line was that I didn't feel that the marriage was what I wanted for myself anymore.
Maybe I'm projecting, but it kind of sounds like that's where her head is at. Her behavior of being critical and complaining may be her way of trying to convince you that the marriage isn't salvageable. Have you asked her if she wants out? Have you asked her to think about whether she wants to continue to "try"?
Divorce isn't the end of the world. I left my first husband amicably, we were able to agree on all of the important issues. My husband was very hurt, but he got counseling for himself and relied heavily on his AA friends for emotional support. We cooperated in raising our kids (he had primary custody but cooperated in keeping me involved in their lives). We are still good friends to this day--I stay with him and his wife when I go out to visit our (now adult) kids.
It just sort of sounds to me like she doesn't have much invested in saving this marriage, and that's something you might have to accept.
I'm sorry for the pain.