Having more than one wife or husband at the same time. Monogamy is the practice of marrying only one spouse. Polygamy is the practice of marrying multiple spouses. Polygyny is the practice of a man marrying multiple spouses.
Polyandry is the practice of a woman marrying multiple spouses. Polyculy/Polycule or group marriage is the practice of both marrying multiple spouses. There is no technical term for group marriages, but we are including these as a form of polygamy.
Polygamy is not fornication, open marriages, “swinging,” or the like with individuals having side relationships for sexual pleasure. These are emotional bonds of marriage where all involved enter into eternal covenants with the Lord.
The Law of Moses clearly allowed for polygamy. Exodus 21:10 mentions that a man may take another wife. The following verse states that she may leave him if he doesn’t care for her financially. Deuteronomy 21:15-17 is clear what to do with an estate if a man had two wives, and only likes one of them.
Deuteronomy 25:5 commands a man to marry his deceased brother’s wife, it gives no exception for him if he is already married. We know the Nephites had this Law, as 5 Moses 22:17- 19 and 25:17 mirror these chapters and verses in Deuteronomy.
We also see the example of Sarah taking multiple husbands in 1 Moses (1 Moses 21:13, 23:15-18, 24:21).
The Lord does not appear care if we are polygamists of monogamists, as long all involved are one with each other and with God, and together they work to keep their covenants with God (Doctrines of the Saints 17d:18). Monogamy appears to be the rule when men are not faithful to their wives (Jacob 2:31, 40-41 RAV, 2:23, 31-32 OPV). Polygamy is not seen as a sexual orientation by law, like heterosexuals or those of the LGBTQ community, but rather as a lifestyle. Thus, it is a choice. That said, some psychologists disagree pointing out that there are those that do identify as polyamorous as their sexual orientation. They and their partners may choose to live in a way that honors their covenants to and with God in polygamy or in monogamy.
See Book of the Law of the Lord 44:5; 5 Moses 25:31-32; Exodus 21:10; Doctrines of the Saints 17a-e