Well most polygamous families do have full time relationships with all of the spouses involved. I mean, it is difficult not to when you're all living in the same house.
yes, but it's a different kind of relationship. it's not like they are all sleeping together or buying gifts for the others for valentine or anything. they don't go out all of them on dates and so on. the wives are all married to the same guy so with him they do but with eachother it's a different kind of relationship.
For the most part. There are some cultures in the world where it is a woman with multiple husbands. I read about one in Singapore back in college, and there are some in parts of Asia and Africa, too. Who knows how those ones are done?