God I suck at using forums. Hope I did this right
I've had male friends in this situation before. I close friend of mine wasn't allowed to party without his girlfriend (ex-girlfriend now). But SHE could go out whenever she wanted without notice.
I've also had female friends in this situation. Usually the prettier types. They'll go out and flirt with guys. But when their boyfriends goes out they get paranoid and it's like 21 questions with them.
I feel this happens for 2 reasons:
1. she's insecure
2. she's really flirty and KNOWS how girls get when talking to cute guys. So when you (a cute guy?) go out, she pictures a swarm of women.
I hope for the latter reason. 'Cause then you can take it as a compliment.
I'm no alpha. However, as a woman, these would be some infuriating/sexy answers you could give her:
OF COURSE there were girls there. Hot girls? Eh, compared to you? No.
On the phone: What am I doing right now? Hold on (pause...) Sorry this chick's being annoying. (make it seem like they're swarming you. But you're still interested in her)
Hope this helps!