LTR 1 year both 19, really good usually. She has local friends that hang around together and there's some guys in the group, approx 5. Due to proximity they're all good friends. They've recently started smoking weed. I don't really go to the parties as I have my own friends. It seems I can't really patrol her smoking weed but also I don't want her to be high with other guys even if her girl friends are around, some of the guys who are clearly DTF with her. If she's high she could get horny and irrational etc etc.

I don't know how to prevent the situation without coming off as needy and controlling and I can't break up really over this as she's only done it once but she plans on doing it again. She's also kinda flirty with people in general and she's very pretty. If I'm not around too and she's high it could lead to cheating etc etc.

What to do?