I'm coming to the end of a 20 year marriage to an alcoholic wife, so I'll apologize now for my abrupt suggestion. I'll strongly advise/inform/plead/scream at you with this:
Run away. Do it fast, without any grandiose speech or even a clue for her to figure it out. Just run away as fast as you can and don't look back.
There is no prize that comes with being in a relationship with an addict. Zero. You don't have to take my word for it. Just read all the posts of the rest of the walking wounded you find here.
And for your own sake, don't ever believe the romantic garbage of a happy ending to this scene in the movie of your life as you are not the cause of her addiction, so you won't be the cure.
Her life is not yours (repeat this to yourself as often as necessary), and what she is doing is sucking the very life from you. And by staying, you are letting her.
You don't have the legal entanglements of a marriage (be SO thankful for that), or kids(even MORE thankful for that), so just do yourself the biggest act of love to yourself and cut and run.
Look for that life, relationship, love that YOU want, because it's really out there. That person is really out there. Just give yourself the space, the distance, the time and whatever else you need to start that next chapter of your life's story, but the first thing you'll need to do is to give yourself that freedom from being with an addict.
And don't worry about her. There is little doubt that she will find someone else to feast on. All vampires do.
I pray you get to that point of doing what's right for you...