Here's a scintillating one that I incorporated (loosely) into the pages of ROOT, PETAL, THORN. This is the fact behind the fiction. My great-great-great (did I get that right?) grandmother, Mary Elizabeth Helm Gordon, was the third wife to her best friend's father. Here is an excerpt from my great-grandma's memories.
Mary had been playing about the neighborhood with other children her age and was especially fond of visiting the home of James Gordon, a man who had two wives and several children, many who were Mary's age. In those days of plural marriage it was not uncommon for an older man to take into his family a young wife. So in the spring of 1857, while Mary was a mere child we might say, she was married to James Gordon, the father of her best friend. [During the years of her marriage to James] Mary gave birth to seven boys and four girls. The first years of married life were filled with toil and child bearing, as they were for all other Pioneer Women.
How did young Mary feel about this turn of events during her care-free childhood? The narrative doesn't divulge and we can only guess, based on our modern view of polygamy. In ROOT, PETAL, THORN, my character Cora Lansing is propositioned in much the same way, but she makes a different decision and follows a very different path.