I'm a guy in my 30's and I have several friends who have had or are in poly relationships. Now, I'm an intolerable prick who can barely make a relationship with a single lady limp along for a few years until it explodes in a fiery shit storm that makes me consider self administered chemical castration, but like all good armchair quarterbacks, I watch and observe and speculate on how I could do it better than my friends. What I've learned so far is pretty telling. All the attempts that I've seen have been one guy and a couple ladies. There seem to be two requirements for any chance of it lasting. First, the ladies have to be into each other. Not just sex, though that's important, but also emotionally. If they don't feel deeply connected, and able to find the same level of comfort in each other's arms as they find with the guy, it won't last. This also implies that the women are not so tragically self esteem damaged that they can't ever stop unfavorably comparing themselves to the other lady. But basically could they be a workable lesbian couple? If yes, proceed. Second, the guy has to be a relatively inoffensive goober. Seriously, he has to be almost like a big adorable puppy dog that is always calming, drama free, and generally just does his own thing. He contributes, of course, and they love him, but it isn't his show. But yeah, imagine some happy lesbians with a big goofy pet boyfriend who knows when to make himself scarce and when to show up with Ben and Jerry's and ready to give back rubs.