EZ, my son has spent most of his adult life in and out of the revolving door of recovery/relapse and went to more than 15 rehabs, most of them 3 months with good resourses like counseling and AA meetings and preparation for staying sober/straight after he left and hit the "real world" again. He had the tools but never used them, he had a sponsor and therapist but dropped them with the first relapse, which came quickly. He went to jail and then his crimes got bigger and he went to prison and is back there now after blowing parole by stealing a car and being caught with thousands of dollars in cash and more in drugs.
Through the years I tried to save him from himself, until I almost died from his addiction. I learned the hard way that I had to let go and let God do for him what I could not. Today I pray for him every morning then live my life well making healthy choices along the way.
My point is that your toxic relationship will not get better any time soon. SHE has to make better choices, and she may over time or she more likely will get worse, like my son. Nothing you say or do can save her. If love could save our addicted loved ones, not one of us would be here.
My suggestion is to cut all contact and take this opportunity to let her go, your heart will heal in time, her addiction may not.
I am glad you came here and hope you find some of your answers and lots of support. You are not alone here.
I wish you well and hope you will give thought to healing yourself and then finding new beginnings that are healthier and that make you happier...as a good relationship should. You don't need to count on anyone to hold the key to your happiness, you hold it and only you can find a happiness in your heart that doesn't depend on anyone else.
Good luck, keep walking in your recovery and don't look back.