Your letter just breaks my heart for the pain you are in. Sadly, her addiction is her number one love and she can not quit for you! I am sure she loves you very much but addiction is just that powerful. It's hard for many of us to understand but addicts are not using drug at us. It's not personal, like we think it is. Their brains have changed and it does everything it can to protect and sustain their addiction.
You certainly have the right to have firm boundaries about what is acceptable to you and in your life but threats and ultimatums are not boundaries and will not help her or you!
Have you ever thought about going to Naranon or Alanon? Maybe a good therapist who understands addiction?
ETA : Weolcome to SR. As always, I am sorry for what brings you here.
