Curly and I sleep apart. She decides who sleeps in her bed and I decide who sleeps in mine. I also much prefer to sleep alone, so these days its very rare that anybody would sleep in my bed besides me.
Beyond that, I'd never regard anyplace I couldn't invite somebody to sleep with me as my regular sleeping space. The moment any partner says "You can't have anybody besides me sleep here" is the moment I find somewhere else to sleep.
Obviously, other folks handle this sort of thing in a different fashion. I'll add to the chorus saying y'all need to sit down and work it out for your own situation.
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.