Exploring what could have been [FMF]

Okay, just a couple of things as a warning/notice before I dive into this:

* This story involves cheating on at least one, but probably multiple people. I know that’s not everyone’s cup of tea, and I’m certainly not proud of it.
* It may not be a story that’s hot in the way you’re used to seeing around here. There’s not even full-on, PIV sex involved. It was hot to me on a fundamental, mind-blowing level, for reasons that will hopefully become clear. I’m writing this down for the first time, mostly as some kind of cathartic relief as I revisit this event in my mind every now and then.
* This will probably be pretty long. Skip to the break if you don’t care about the prologue/build up, although I think the build-up helps provide some important context.