I'm sorry, DII. I wish I could come up with an answer for you, but there really isn't one (I know you know that already but....well.....)
I know that I reached a point where I was no longer "in love." I loved the person he was when he was sober, but could no longer stand the torture of waiting for the next relapse. It was interfering with my ability to be happy in my day to day life, and life became a series of events and nothing more.
I wanted to feel joyful again. I wanted to feel "in love" again. And I knew those things were not going to happen as long as I remained in the relationship....too much damage had been done. I could love and support him but I couldn't have back the trust and intimacy that had been wrecked - EVER. So I made the right decision for myself. I can't say what the right decision might be for you.
But I will wish you the clarity and detachment to make it for yourself, and know that whatever you choose, as long as it comes from a place of honesty and compassion for yourself, it will be okay.
You can only live your life. You can't live hers for her, or magically take away the effects of her poor choices. One of those effects is that you can't get back the feelings you had before. That's very sad but...you didn't cause it, you can't control it, you can't cure it. And life goes on.
Strength,
GL