<human>: I'll keep this short. My girlfriend is "friends" (i.e., they chat sometimes on Facebook, that sort of thing) with a lot of her ex-boyfriends. No problems there. She has also slept with a number of her male friends -- either one-night stands or in ongoing FWB arrangements. Okay, I'm not the jealous type -- having slept with a couple of my female friends back in the day -- and she really only sees these people at parties every 3-4 months or so (and I'm usually there too). 

This week, though, she wants to go hang out one-on-one with a friend she used to have sex with, to watch a movie at his apartment. I haven't talked to her about it yet because I'm not sure how I feel about it. In your opinion, is this crossing a line? It does seem a little weird. And my second question: I don't want to come across as jealous / possessive / needy if I confront her about this. What's the best way to broach this, in your opinion?

Summarize the given text in a few sentences.
<bot>: Girlfriend wants to hang out one on one with a former FWB. Not sure if I should accept this, and if not, how to confront her without seeming jealous and possessive.