Christian standards were often derived (and have been since derived) from the culture that they live in. Polygamy is still ok among Christians in parts of Africa. That Chrstianity did not promote polygamy and moved away from it is likely based in that Christianity was a Roman institution after a few centuries in addition to originating in the Roman world. That being said, polygamy has been openly practiced by Christians in various parts of the world since the beginning of the religion.
There is a contingent of "christian polygamists" that are not fundamentalist mormons in the US. The thought regarding the scriptures that direct that an overseer be the husband of one wife is that it means that the husband should at least have one wife. Single men were not qualified to be overseers of a congregation since they had not proven anything about their ability to even lead a household -how could he be qualified to lead the household of the saints?
Polygamy serves purposes in communities that go beyond supplying a man with more sexual partners. But they don't usually apply in the western world in any way that we really can comprehend when we have life insurance, social security and a social safety net for widows/orphans.
I don't think the Bible forbids it, but common sense should do so in the west.