Anyone tried it or want to? Me and my boyfriend went into an open relationship about a month ago, and honestly it's been the best thing for our relationship for I think one main reason. Variety! We get a wide array of penises and vaginas to choose from, we're more comfortable and sex positive now as a couple and it's generally helped re-light the flame after two years together. If we have kinks we want to explore but the other is dead against, we can try them with others. Plus, I'm 19, I'm never gonna have this kind of stamina again. So I want to know whether other poly people have had similar experiences or different, whether you've tried it and gone back to monogamy. Also, monogamous people, would you try it? I couldn't go back to monogamy now personally.
We swing, which suits us both very well. We know three women living together in a polyamorous relationship which has been going on for several years, and come across people in open relationships now and again. No idea how that works for them, but it isn't unusual.
These days any sort of sexual relationships are OK, but make sure both of you are OK with whatever yours is, and keep on talking.
I'm 30 and wish I had the stamina I had when I was 19, haha! 
I finally came out as polyamorous about a year ago. Until then, I was either in monogamous relationships (but none seemed to fit me), or single, or single and had fuck buddies. At the moment I have two boyfriends who are monogamous to me, as well as some play partners. I've found what works for me and can't imagine me going back to monogamy.
However, the only thing that matters is what you want. Then you can determine which kind(s) of relationship(s) fit you and find partners that match your lifestyle. =)