At a Christmas party about 12 years ago I ran into a woman that I had been on a couple of dates with. Because she and a her girlfriend at the party were drinkin

At a Christmas party about 12 years ago I ran into a woman that I had been on a couple of dates with. Because she and a her girlfriend at the party were drinking I offered to drive them home. On the way home her girlfriend got a call, learned of a swingers party, and invited us to go with her. It was quite surprising for me. We didn't stay or participate, but I had no idea that such well attended parties were going on under my nose and overlapped to such a large degree with my social circle. (This wasn't in SV.)