So I didn't have sex with anyone tonight. I went home early, and in a crappy mood.
The problem wasn't sexual, but social. The party basically consisted of about a hundred people in a big hall with very loud bad music. It was too loud to have a conversation, so I couldn't meet new people and I couldn't say much to my friends. My friends had all come with one or more partners and I was ranked at about ninth wheel. I'm not good at dancing and I'm not entertained by drinking. I never even made it to the part of the night with sex; after two and a half hours of reliving my middle-school dances I was too bored and lonely to stick it out any longer.
(I had an epically bad night at work the night before, too. Sometimes going straight from a bloodbath to play can be cathartic, but when the play situation ends up being itself stressful, I just melt down. Handling mutilated corpses and getting 3 hours of sleep is rather poor preparation for taking this shit gracefully.)
Ultimately it was really a hearing problem. I'm very bad at understanding conversation where there's loud music. My problem really isn't with swinging or my friends or any such drama; my problem was just that I couldn't communicate, and it left me feeling profoundly lonely. Maybe someday I'll try going again and bring a TTY machine.