Sarah Whitney was one of the victims of Joe Smith. She became a plural wife of Smith, and this insightful link will tell you how Joe wanted her to sneak over to where he was staying for a "visit," since Emma wasn't around. Furthermore, nine months after her plural marriage to Joey, Joe allowed her to be married to another man to cover up the fact she was his plural wife. That's polyandry! I love the part of the letter where Joey says that he thinks Emma won't be around! This nuttiness is the stuff cults are made of:
https://user.xmission.com/~research/family/strange.htm
And, of course, no Mormon will acknowledge that Smith was a liar and a lech.