CES LETTER CLAIM
Did Joseph Smith have an affair with Fanny Alger?
Numerous people called it a marriage... While Oliver Cowdery may have thought it was an affair; others, including ex-Mormons, thought it was a marriage.
Plural marriage is one principle of celestial or eternal marriage. However, when allowed by God, polygamy for time could be practiced. Joseph was married to three widows who were sealed to their deceased husbands. Similarly, his plural marriage to Fanny was not an eternal marriage.
An excellent resource of primary documents pertaining to Fanny can be found at MormonR - Joseph Smith and Fanny Alger