First post on this forum
We're not newbies though; we got into doing this more than 15 years ago now (wow! has it been that long?).
I voted "Other... .Explain in a reply.", so here I am
Before my wife and I met, I'd been briefly involved in a poly triad. I was friends with the husband, and lover with the wife. It ended because of growing instability in their marriage (not caused by me or based at all on the wife having a lover) that eventually led to them divorcing. Fast forward a bit, and I met my (now) wife. As is usual, past sexual experiences eventually became topics of conversation. My (now) wife was upset with the idea that I had contributed to a woman cheating on her husband. I explained it wasn't cheating at all; the husband knew and approved of his wife having sex with me, approved of she and I having a relationship, and he and I were friends through it all. My (now) wife was disgruntled by it, and made it clear she had no interest in such things. That was fine with me; I didn't
need non-monogamy for myself or for her. The subject was dropped, and all was good. We dated for a while longer, got married, all is marital bliss. And then...
~5 years into our marriage, we're in bed and I'm massaging her (which she loves) and out of the blue she says "It would be enjoyable to have two men massaging me at once". I was dumbstruck. Never in a million years did I ever expect she would say something like that. Further, it wasn't even on my mind. That part of my life was in the past, and I was a happy, content, monogamous husband married to a happy, content, monogamous wife.
After much research, discussion, soul searching, etc. etc. etc...eight months later we're having our first MFM. It went ok, but not stellar. We'd already decided before getting into this that we wouldn't judge all of it based on a handful of encounters. So, onto the next MFM. That was ok too, but not stellar either. The third time ('s the charm?), we're in a MMFM. My wife is getting to have sex with three of us. One of the other two guys in particular she is enjoying VERY much. The sounds she is making are absolutely delicious, and while they're having sex her toes are literally curling. She. Could. Not. Get. Enough. Sex. From. Him. We came away from that evening, she gets in the car, and she says "Ok, NOW I'm a swinger!" with a huge grin on her face. Really, it's hotwifing to that point. A week later, she went on her first solo date with the same guy, and they had sex literally for hours.
The rest, as they say, is history. So, "other" for us...I introduced her to the idea of non-monogamy, but years later it was her picking up the banner and running with it.