I get this question a lot, mostly from people who are not in but curious about open or poly relationships:
Have you ever had a threesome?
To which the answer is “yes”, but to the implied question–“Do you and Carrie seek out/date/sleep with people together”–the answer is “no”, or maybe “we haven’t”.
I have had sex with two partners, but only when I was single (I don’t have any experience with foursomes or moresomes or sex parties or such). It was fine. My limited experience has led me to the conclusion that–for me–multiple-partner sex is all right, but not enough better than single partner sex to justify the added logistical difficulty.
Partly, I think I just lack that particular fetish, which means that I don’t find the situation inherently hot. I like looking at naked attractive people as much as the next human being, but it doesn’t go beyond that for me. Also, my particular kink pattern tends to include a sense of responsibility for everyone else’s pleasure, which is fine one-on-one but starts to get distracting with multiple partners.
I also suspect that the majority of people–or at least men–with this particular fantasy haven’t really thought it through. Can you rub your belly and pat your head at the same time? Some of us can, most of us can’t, and that’s without the other distractions of sex. Three is a weird number–at least one person has to be doing two things at once at all times, or doing one thing while something very distracting is happening, or else someone is likely bored. I really enjoy giving oral or manual stimulation, but doing it right requires some real concentration. It’s also for this reason that “69” stuff is less interesting to me than it’s apparently supposed to be.
In any event, many people–Carrie included–have suggested that maybe my relative lack of interest stems from the circumstances of my forays into this territory. I.e., hooking up with strangers always sounds hotter than it is, and the dynamics are entirely different with someone you know and have affection for. Which is possible, but the other thing about multiple-partner sex is that it just takes a lot of arrangement or else a weird confluence of circumstances. In general, someone has to be really into the idea, and I’m not and Carrie is only circumstantially so. Most couples that go down this route seem to end up spending a lot of time and energy unicorn hunting, and neither of us is strongly inclined to do so. We’d probably have to be hunted down by some enterprising unicorn with a couple crush.
Which is mostly to say that, much like the “what, you mean like two girlfriends” stereotype, the questions that people tend to ask before getting into open relationships are mostly the wrong questions.