Complicated topic?

okay so my girlfriends cousin invited her to go out one time to smoke and chill with friends and to keep one of her boyfriend friends company but my girlfriend said no, so I was glad…but still she ended up telling my girlfriend that instead of taking my girlfriend she took another girl to hang out with her boyfriend friend and they had sex… so long story short she’s a really bad influence and she wanted my girlfriend to sleep I Ma hotel with her boyfriend homie… what should I do?😶😐
Complicated topic?
Post Opinion