Zug zug fun!
I've enjoyed sex in many different circumstances, some of which involved some degree of attachment--from friendship to deep involvement--and others which involved nothing more than lust or simple pleasure-seeking.
I had to figure out long ago if I was wanting sex with some woman just due to hormones or if there was some emotional attachment involved. There were some problems when I thought I wanted sex due to emotions and it turned out I just wanted the physical pleasure. I learned early that lust is different from infatuation is different from friendship is different from love.
When speaking of various forms of non-monogamy...it ain't poly if you're just fucking around.
While polyamory, open relationships, and swinging are all distinctly different approaches to non-monogamy, they are not mutually exlusive. Folks can, and some do, engage in more than one of them at a time--and it's all good.