This post originally appeared on Theological Matters at https://theologicalmatters.com/2017/10/10/the-new-marriage-battleground-polygamy-polyamory-and-open-marriage/.
Students who have taken my Christian Home class are familiar with a diagram I draw on the board each semester. In this diagram, I visually depict the difference between polygamy and polyamory—two marriage arrangements that contrast monogamy. I then tell my students that such arrangements will most likely be legal in the United States in just a matter of years and that the church will need to be prepared to address them.
The timeframe for normalization of these alternative marriages may have accelerated in recent months as a series of articles have been published touting the advantages of various forms of multiple marriage. It is important for us to understand what these are and to critique them from a biblical perspective.
The Marriage Alternatives
Until the last couple of years, laws in the United States only recognized marriage to be between one man and one woman. The 2015 Supreme Court decision in Obergefell v. Hodges opened the door to same-sex marriage. Now we see a push for different types of marriage that infringe upon monogamy.
Polygamy is a marriage arrangement where one individual is married to multiple partners. Historically this is primarily a man married to multiple women. This form of marriage is the one most clearly set up for legalization through the Obergefell decision.
Polyamory literally means “many loves” and describes “consensually non-monogamous relationships [where] there is an open agreement that one, both, or all individuals involved in a romantic relationship may also have other sexual and/or romantic partners.” Polyamory differs from polygamy because all partners can be in multiple marriage-like relationships. While a recent Christian blogger has stated that polyamory is not about sex, the basic premise of this type of relationship is that the various partners are in multiple intimate, romantic, sexual relationships.
Open marriage is the third alternative in the marriage battleground. This arrangement involves couples in the marriage being open to romantic, sexual relationships outside the context of their own marriage. In some respects this is similar to polyamory, although the outside relationships may not be formalized as marriage. Proponents of open marriage argue that as long as both spouses are in agreement with the arrangement then it does not break the fidelity of the marriage bond.
The Battle Ahead
Are these marriage alternatives really going to become mainstream? Numerous articles have appeared over the last year promoting these different marriage arrangements. New York published an article promoting consensual nonmonogamy. The Chronicle of Higher Education interviewed philosopher Carrie Jenkins about her new book What Love Is and What It Could Be in which she promotes polyamory. NPR even ran a story about the cultural moment for polyamory stating, “Lately, I’m seeing ‘polyamory’ everywhere. It’s not a new word or concept of course, but it seems to be having a cultural moment.” Polygamy is popularized on the television shows Sister Wives and Polygamy USA.
From a Christian perspective, progressive Christian blogger Chuck McKnight is currently publishing a series of blog posts promoting polyamory and open marriage based on a “love-based ethic” in which our ethical actions are judged by only the question of whether they are loving. McKnight believes that polyamory can be loving and therefore not biblically prohibited.
The Christian Response
In response to the cultural push for acceptance of these marriage alternatives, Scripture gives us a couple of clear ideas about marriage.
Scripture communicates a consistent message about the monogamous nature of marriage. Beginning in Genesis, we see that God’s design for marriage is a comprehensive, covenantal relationship between one man and one woman. Genesis 2:24 provides this divine commentary on the nature of marriage:
For this reason a man shall leave his father and his mother, and be joined to his wife; and they shall become one flesh.
God designed that the man (singular) would be joined to his wife (singular) in marriage. All subsequent descriptions of marriage relate the ideal of monogamy. While there are examples of polygamists in the Old Testament (for example, Lamech, Abraham, Jacob, David, and Solomon), their polygamy is not depicted as ideal. In fact, their polygamy is the source of great strife and conflict in their homes. Despite the presence of such polygamy, the overwhelming testimony of Scripture points to monogamy as the standard. Both Jesus and Paul affirm the monogamous standard. In Matthew 19 and Mark 10, Jesus quotes Genesis 2:24 and then describes two becoming one flesh. He never inserts a third or fourth individual into the marriage. In 1 Corinthians 7, Paul states, “But because of immoralities, each man is to have his own wife, and each woman is to have her own husband” (1 Corinthians 7:2). Paul clearly communicates the idea of monogamous marriage here. The message is consistent throughout Scripture.
Any departure from monogamous marriage is a form of sexual immorality. Scripture consistently condemns adultery, but two specific passages come to mind in response to the current challenges to marriage. In Romans 7:3 we read, “So then, if while her husband is living she is joined to another man, she shall be called an adulteress. . . .” Paul describes a standard monogamous marriage (a wife with one husband) and equates any union with another man as adultery. In addition the author of Hebrews tells us, “Marriage is to be held in honor among all, and the marriage bed is to be undefiled; for fornicators and adulterers God will judge” (Hebrews 13:4).
If Scripture depicts God’s design for marriage to be monogamous, and if any departure from monogamous marriage is equated with adultery, then the various alternative marriage arrangements—polygamy, polyamory, and open marriage—are all forms of adultery that are subject to the judgment of God. Therefore, Christians should not endorse these forms of “marriage,” nor should they tolerate them within their midst. Just as Paul rebuked the church at Corinth for tolerating the man who had married his father’s wife, we too should rebuke those who promote and tolerate such distortions of God’s design for marriage.
 Rhonda N. Balzarini, et al., “Perceptions of primary and secondary relationships in polyamory,” PLoS ONE 12 (2017).
 Churck McKnight, “What Polyamory Is Not,” Hippie Heretic (September 11, 2017).
 Drake Baer, “Maybe Monogamy Isn’t the Only Way to Love,” New York (March 6, 2017).
 Moira Weigel, “‘I Have Multiple Loves’: Carrie Jenkins makes the philosophical case for polyamory,” The Chronical of Higher Education (February 3, 2017). Carrie Jenkins, What Love Is: And What It Could Be (New York: Basic Books, 2017).
 Barbara J. King, “A Cultural Moment for Polyamory,” NPR (March 23, 2017).