Addicts are two people. You have the real version of them, the loving caring funny intelligent person, and then you have the drug version – the selfish, uncaring, rude, arrogant, denying, lying a**hole. That is a universal truth, whoever the person. They will sell their granny to get their drugs and have NO compunction lying.
So unless your partner sees the problem in her use, there is literally NO hope for you. And yes, it’s heartbreaking. No only losing the true person, but also dealing with the damage they cause you, the pain, the heartache, the sense of loss..
you really have to deal with your heartache and start to resolve these things, so that you can find peace. Heartache doesn’t last forever.