Hi G.!
I am Dawn a recovering pill addict with 6 1/2 years of clean time.
I don't think you should worry about what to say or what not to say. You do not need that added stress of worrying about whether you are saying " the right thing" or not. Speak the truth, in love and let the chips fall where they may. You must remember this......The only person who will cause your girlfriend to use is your girlfriend. She is in control of herself. She may try to blame you, but don't buy into it. We all have reasons we have sought the mind altering substance, but to blame others is rotten.
Go to a meeting. Let us know how it goes.
Peace from the other side of the ocean!!!
