So my wife and I have been “swingers” for a few years now. I use quotation marks because we’re not big on the swinger party scene, we’re fairly picky with who we play with. But I certainly wouldn’t go as far as to say we’re poly.
Anyways, labels aside, it started with a mini vacation we did with a few of our friends. In grad school I met two women I got along really well with, Mary and Jenni. After our masters program was over we remained good friends, and when Mary started seeing another guy from our university, Oliver, all 5 of us would hang out regularly.
As far as swinging goes, my wife and I joked about it for years. We have a tendency to never really sit down and talk seriously about things. We joke for a while about it, teasing the other, kind of gauging how the other feels about it. I could tell based on our jokes as well as our pillow talk that both of us were somewhat interested in it.