Originally Posted by
evenkeel 
'They do so by detaching - in otherwords, they build lives for themselves away from their partners, they ignore their partners when they are being abusive, they dont fuss over them, they dont react to bad behaviours and they treat them with respect, which is a really tough call and its certainly not for everyone.'
THIS. This is exactly what my mother-in-law is doing with my father-in-law, though in the last year she's been fighting back verbally when he goes off. She's also FINALLY stopped buying him his beer. She had many reasons not to fight back or leave him before (first kids and then her mother living with them) but now that the kids are out of the house and grandma has passed away she's finally starting to build up the courage to go. I see this as what I have been doing and would continue to do if I decided to stay. But you're right, it's not good for me and hasn't been working so far. It's "where do I go from here" that's the issue.
Your MIL hasnt been practicing detachment very well if she has been fighting back verbally and buying beer - this isnt detachment. You need to do everything in your power not to react to their drinking, that way they can not blame you as to why they are drinking and they have to look at themselves. In some alcoholics this works and can bring about sobriety and in others they still continue to drink. Thats their choice and your choice to stay if you wish. Reacting to them only prolongs the drinking and just serves to make you stressed and upset.
As I said it takes a very special person to detach and many of us, including me, have tried and failed.
Buying beer for them is a whole other story and is definitely a no no!