Rebecca Walsh had a good editorial piece in the Salt Lake Tribune about the Warren Jeffs conviction . In the article she compares polygamy to a weed that you cannot get rid of. She then explains:
"Part of the problem is that The Church of Jesus Christ of Latter-day Saints has given up polygamy on earth, but not in heaven. Church faithful commonly are taught that plural marriage is possible in the hereafter. It's part of the eternal family model for the celestial kingdom. That might help "fundamentalist Mormons" justify their complicated families."
I stated something similar in a blog article last year. It generated some good discussion, and two of my LDS friends were able to weigh in with their perspective.
It is a complicated issue and the nuances run deeper than it initially appears.