i know exactly what you are going through. I am going through the same thing except with a pain pill addiction.
As hard as it is to accept, there is nothing we can do except take care of ourselves.
My addict will not admit there is a problem, althougth all the signs are there. And when he realized i was on to him, he left me.
I know that it is for the best and you need to think about this too. they have to want to help themselves and until that happens, our hands are tied. Do not let her drag you down with her.
One thing I have learned....no matter how much they love us...we can never compete with the addiction. It will always come first. I know that is a hard pill to swallow, but it is unfortunatly the truth.
I wish you much luck my friend, and my thoughts and prayers are with you.