Your desire and commitment to save her is both beautiful and admirable.
Alas it's futile. I tried and failed to save my alcoholic father and didn't listen to a soul who told me it couldn't be done.
He too teased me with short periods of sobriety but after a boyhood and adulthood of pain and suffering watching him drink he eventually proved me wrong by dying from alcoholism.
He then proved me a fool by my becoming an alcoholic myself.
If you stay with her, please know fully what is at stake here because you could be signing up for a lifetime of dissapointed and heartbreak......all of which can become an addiction too.
All said with love.