Have any women (or men) been involved in a spontaneous gangbang that has just happened because the circumstances were right at the time.
My wife was in a situation like that only once, it was with three guys, would like to hear other peoples experiences.

It happened to us while we were engaged. The circumstances just worked out thanks to alcohol and a fantasy of hers (that I was ok with). A good friend of mine and his friend ended up joining in cause they were crashing at our house after we had gone out. My friend walked in our room asking where he could find an extra blanket and I had her bent over the bed. He made some joke about watching, she made a joke about getting his friend to watch too and before we knew it was 4 of us in the room. They really were just watching at first but it then it was touching and when she got pretty worked up she seemed to be up for more. Its a little weird watching other guys fuck your future wife but she was loving it and it turned out to be very hot to watch. She was pretty upset for a solid week, I think mostly because she didn't know the one guy, but she eventually got over it. We still go out to dinner with the guys and their girlfriends but the girls don't know the story.

It can be rather funny (not in a laughing sort of a way) how seemingly sweet innocent girls can change under different circumstances, your fiancée must have been in the right mood at the right time for it to happen like it happened and it must have a little weird for you watching other guys fuck your fiancée.
We were 35 and married 15 years when my wife went with her first ever other guy (I took her cherry when she was 19) and watching her going with another guy for the first time (but not the last by a long shoot) had me thinking what sort of exchanges were in store for us, as it turned out they were all good changes, my wife never touches Alcohol so all the playing she has done she has done stone cold sober “out of pure lust I keep telling her”.
But as I said it all worked out for the better and we have now been married close to 50 years and are still playing, do you think it might happen again with your fiancée or wife?