Now that the LDS Church has officially put up information on lds.org about Joseph Smith's polyandry, let's see what the Church has to say about it.
Joseph Smith was sealed to a number of women who were already married. Neither these women nor Joseph explained much about these sealings, though several women said they were for eternity alone. Other women left no records, making it unknown whether their sealings were for time and eternity or were for eternity alone.
What's an "eternity alone" marriage? Here's the explanation:
Eternity-only sealings indicated relationships in the next life alone.
"Relationships" means sexual relationships; it seems that some of Joseph's marriages would only involve sex after death and resurrection.
So relax, there's a chance that Joseph wasn't boning all of the already married women that he secretly married. BUT THEY'LL BE GETTING IT ON INFINITELY IN THE NEXT LIFE.
Does that sound any less weird? Does "eternity alone" even make sense given how long eternity is? What about postponing sex makes having multiple spouses sound more acceptable to Mormons? I wonder how the husbands feel about this arrangement? Wouldn't a "life alone" marriage at least offer the relief of knowing that your wife's relationship with another man will one day end?