JOEL - At the present time The Church of Jesus Christ of Latter-day Saints(Mormons) does NOT consider polygamy acceptable. There was a time before 1890 when God commanded that the doctrine of plural marriage should be lived (1850-1890). We believe it is possible that God may ask us to live it again in the future. But after the laws changed in 1890 making the practice illegal, the Church discontinued the practice as directed by God. Today any church member practicing polygamy is excommunicated from the church. Before 1890 there were no Mormons practicing polygamy in other countries, so that was not a problem.
Any other groups of people who practice polygamy today are not members of the Mormon Church, even though the roots of their religion may have originated with the Mormon Church before 1890. I have more information about this subject at the following site:
http://www.mormonhaven.com/polygamy.htm