I think it's possible for a polygymous relationship to work, but it would require certain circumstances. I had a girlfriend who wanted to have a girlfriend, as she was exploring her sexuality, and was learning that she was bisexual. I personally didn't have a problem with it, even if I didn't find the woman attractive myself. I mean I wouldn't have minded a 3some, but it didn't really phase me. I had seen pictures of the girl, and she was pretty, but she didn't really stir my loins. But I equally didn't feel threatened by her either. To me, having a relationship with a woman would be a type of relationship I couldn't provide. That girl/girl nature, and no I don't mean the sex, I mean the mentality aspect, isn't something I could replicate. So I didn't really have a problem with it personally. She seemed kind of surprised by this. We broke up shortly after that, mainly because she was really mentally/emotionally unstable, but the possible 3 way relationship wasn't a factor.
I have a friend online who was in a relationship with...I think it was 5 people total? 2 guys and 3 girls, and they were pretty interchangeable about the sex stuff. They seemed to have a pretty good relationship, but it didn't last, there was some animosity between some of the members, and some jealousy, but it all seemed to be from 1 person, so maybe without that person it would've been fine. *shrugs*
I dunno, I don't see a problem with it, I don't think it's any sign of God that you are more blessed than anyone else, since I don't believe in God, I find that reason total bullshit. I do think, given our current cultures views on sexuality and morality, it is hard to pull it off, because most of the people in the relationship, are coming into it with a pre-programmed mindset that is contrary to polygomy, and dumps a ton of pre-loaded guilt and shame for taking part in such a relationship.