I don't know your situation explicitly, nor am i a woman, but it seems to me like she has convinced herself that she needsto quit smoking weed, and she's blaming her inability to quit on you having weed all the time. Seems like rubbish to me, as you said that SHE went out and bought a bag because she wanted a smoke...it's not like you gave in and supplied it to her. If i were you i would keep the box and keep smoking, but refuse to smoke with her even if she comes to you and says "Oh im bored, lets have a smoke"