There aren't many people in Wyoming, in general. I had to pick up a truck in Wheatland for delivery in Milwaukee and I'm pretty certain I saw more critters than people in Wyoming.
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.