From this Review of Compton's book on Joseph's polygamous wives
The Partridge Sisters: A Plural Marriage Case Study
According to Compton, the cases of Emily (19) and Eliza (22) Partridge contain elements common to many of Josephs plural marriage:
"Emily Partridge provides us with a classic example of the central pattern examined in this book: polygamy may be sacred in theory, but when practiced on a day-to-day basis the plural wife is not given financial or emotional support. In Nauvoo Joseph taught Emily the principle of plural, celestial marriage, and married her and Eliza, but then acquiesced to Emmas browbeatings and consented to his new wives expulsion from his home. Then he allowed the marriages to lapse, apparently taking the unions less seriously than did the Partridges. It should be remembered that he had at least thirty other wives to turn to at the time. After Josephs death, Emily married Brigham Young in open polygamy, but from the beginning of the marriage to its end she was less than a full wife in his family. During the exodus from Nauvoo, the haunting image of the lonely wife standing with new-born baby in the snow shows Emilys lack of practical marital support. . . . Her diary entries expressing her resentment form a significant document, a moving cri de coeur against a non-supportive polygamous husband. The fact that this husband was the prophet and president of the church added a note of cognitive dissonance to her journal, for her religion demanded that she see him as an inspired religious leader. Her words of praise for Brigham after his death show her highly developed capacity for Christian forgiveness" (p. 432).
It was allegedly commanded by God but had to be kept secret, especially from Emma.
What a prophet!