Question: What was the nature of Joseph Smith's "polyandrous" marriages?

Evidence indicates that Joseph was sealed for eternity to eight to eleven women who were married to other men

The fact that these women continue to live with their earthly husbands and even have children by them indicates that the sealings to Joseph Smith were not marriages in the normal sense.

Joseph's sealing to their wives doesn't appear to have changed anything in their daily lives or their relationship to their current husbands

The relationship between these women and their husbands appear to have not changed even after they were sealed to Joseph Smith. Of the eight well-documented cases, five of the husbands were Latter-day Saints, and the other three were either not active in or not associated with the Church. In all cases, these women continued to live with their husbands, most of them doing so until their husbands died. These eternal marriages appear to have had little effect upon the lives of the women involved, with the exception that they would be sealed to Joseph in the afterlife rather than to their earthly husbands.

Notes

Question: What was the nature of Joseph Smith's "polyandrous" marriages?