Many here at SR will advocate leaving and, for the most part, I agree with them, especially when I read about the physical and emotional abuse they go through every day. My heart breaks when I hear the stories of their daily lives. I can assure you that, unless your wife decides to begin her recovery, it is destined to get worse and will eventually become fatal.
You will need to take the path that works for you. It's a bit easier in the sense that your children are adults and don't live with you. It comes down to just you and your wife and how muich you are willing to endure.
Someone else here, another man, wrote that he stayed as long as he could because of pity. I'd like to think that I am staying for love but I am thinking it may be a combination of both. I made the decision to stay and, thankfully nobody here at SR tells me: "we told you so" when I come here for help when I've had a bad day.
For those experiencing physical or verbal violence, I'm willing to say they need to leave and find their peace and happiness elsewhere. In my case there is no physical violence but the emotional turmoil has driven me into a very deep hole of despair that I am still trying to climb out of.
I know you have tried to fix this but you can't. I'm not sure if someone has recommended this to you but I would suggest reading the book: CoDependent No More by Melody Beattie. I found that helped me alot to cope. It may help you decide your path.