TIL that Concubines are legit as per George Q. Cannon, member of the first presidency. "Living in sin" with a girlfriend while married if you eventually take her to the temple is tots legit

Church leader, George M. Cannon suggested the concubinage method of plural marriage to Abraham Cannon (his son) and said, "I believe in concubinage, or some plan whereby men and women can live together under sacred ordinances and vows until they can be married." He insisted that such relationships must be kept secret until the government changed its laws. He added that concubinage would open up a way to take care of "our surplus girls" as well as fulfill the command to multiply and replenish the earth.

Despite protests by contemporary Mormons that polygamy established high standards of decency and morality, and was different than adultery or keeping mistresses, Cannon's behavior proves otherwise. Fifteen lines are cut out of his diary for October 1894, three days after his visit with Annie and Uncle George Q. Cannon, where the suggestion regarding concubinage was made. Though Annie lived to be 79 years of age, there is no record of her having been married. She is said to have accompanied Abraham Cannon on numerous excursions and she refused a proposal for marriage from prominent LDS member, Heber Bennion. (Solemn Covenant, pp. 214-215)