Johnnie
If you truly love her you have to let her go for her sake too. I don't know your story but she's an addict. You cant change her - I think you understand that. When you are in a relationship with her your as messed up as she is. It cant be good for her either.
If you cant let go of her for you - then try thinking about letting go of her for her sake - because you love her.
I let go of mine (I love her very deeply). I did it also for her sake. The relationship wasn't working & certainly was taking a toll on her. I did not want to hurt her by this crazy starting up & stopping the relationship merry go round. It wasn't fair to her or me.
If you truly love her - let her go - for her own sake.
Yes these are easy words for someone to say. But I am living through it right now this minute. So I understand completely how you feel.