21% of Americans have experimented with consensual non-monogamy at some point in their lives, far more than two decades ago Not only do I not believe that statistic, but the footnote citation seems to be broken. I've never seen a poly relationship make it past 10 years and I've never seen a poly relationship without significant issues that you wouldn't see in a monogamous relationship. Furthermore, there simply isn't…
I think you're making the claim much bigger than it is. The narrow interpretation of "consensual non-monogamy" does not imply a relationship. Having a threesome with your partner and your best friend already qualifies. Making out with a non-partner while your partner watches might already qualify, depending on how the question is understood.
I don't think it does qualify any more than having a one night stand between two single people implies that they are dating
This seems to be ignore that Poly implies a relationship, not just sex