Haven't heard of that happening in the game. Didn't even know it was possible. (Although apparently Dr. Vu lobbied hard to include polygamy in the game, based on "his own personal experience." This was for a while a running joke as the explanation for anything weird in the game. "Dr. Vu's experience." I keep meaning to ask him, in a chat, about whether that was the inspiration for how alien abductions are handled . . . heh.)
Anyway, on polyandry (one woman with multiple husbands), it is or was practiced in Tibet, parts of India, Nepal, and other countries in that general region, according to
http://en.wikipedia.org/wiki/Polyandry. It's generally an economically motivated arrangement, sociallogically speaking. In fraternal polyandry, two brothers can marry the same women which means they don't have to divide their estate, and in a culture where at least some of the men are gone at any given time it helps to create a more stable household. That said, it's unusual, because there are fairly specific sociological conditions needed for it to be advantageous, whereas the more common form of polygamy (polygyny, multiple wives) has the fairly self evident and universal benefit of allowing a man (with enough means) to greatly increase the number of children he can have.
Enough sociology. It would be interesting to see if this effect is reproducible, since it would be nice in some situations to be able to have sims get married to more than one other sim at the same time.
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