Is it pretty much assumed at this point that most people have had threesomes, foursomes, or been in an open/swinger relatonship?

Lately I've been noticing more and more that a lot of people I encounter out there in the dating world online and off have had at least one experience involving a threesome, foursome, an open relationship, or they and their former partners played along with other couples. It's very normal, professional, attractive and educated people, too, on top of those who some might describe as more hipster/alternative types you'd not be as surprised to find that out. I also come across a lot more younger couples both dating or married who are into swinging.

No judgement on my end, but I have to admit that the realization makes me feel pretty behind the curve on the current level of experiences of people in their late 20s/30s.