Gf doesn't want me to go on a coed snowboarding trip
I've been dating this awesome girl for 1.5 years now (we're 25) and things have gone really well until winter. I've gotten really into snowboarding for the few years and went to Colorado in a coed group the last two years. When I went last year she was extremely pissed because I'd be sleeping in a house with other girls (obviously in different bedrooms). The people I go with are all friends (she knows some but not all of them). Half of the girls will probably be bringing their bf's with. She's not OK with me going again this year and would break up if I went. I've introduced her to the people going on the trip (of which one wife was drunk and flirty, that didn't help my girlfriend feel any better) and ever offered to pay for her flight with my points. I am going on another trip that's all guys but really wanted to go on this trip too if possible. Would like some advice please.
tl;dr: Gf doesn't want me to go on a coed snowboarding trip and I've even offered to pay for a flight for her to come along, any advice?