Monogamy

What is monogamy?

Monogamy is the relationship form in which, at any given moment, you live with one partner and promise that partner faithfulness. The Algemeen Nederlands Woordenboek adds that you keep that faithfulness as a way of life or as a rule. So monogamy is an agreement, not a feeling.

What monogamy looks like in the Netherlands

Like the default nobody chose, because it was already there.

The Netherlands regulates monogamy hard on one point and no further. Article 33 of Book 1 of the Civil Code reads: “A person can be joined in marriage with only one other person at a time.” That is where the law stops. Whether flirting is allowed is written nowhere.

That people do want that form shows in the Monitor Seksuele Gezondheid 2023 by Rutgers, RIVM and CBS, among more than fifteen thousand Dutch people aged 18 to 80: three-quarters have a steady partner, and 84 percent of that group want the relationship to be forever.

An ordinary example. A couple ten years together call themselves monogamous without hesitating. Ask further, and it turns out one thinks kissing at a party is inside the agreement and the other far outside it. Neither is lying. It was never said out loud.

Where monogamy comes from

From culture, not nature, and much more recently than most people think.

Joseph Henrich, Robert Boyd and Peter Richerson describe in Philosophical Transactions of the Royal Society B how exceptional the form is. In the Ethnographic Atlas, with marriage data from 1,231 societies, exclusive monogamy occurs in roughly 15 percent; in about 85 percent men may marry several women.

And yet monogamy is now the norm in nearly every wealthy country, and it only became so in the last few centuries: Japan banned polygyny in 1880, China in 1953, India in 1955 and Nepal in 1963. The researchers explain that spread not from instinct but from group advantage. Where fewer men stay unmarried, crime figures drop and male effort shifts toward raising children.

Monogamy feels obvious because you grew up in it, not because the species works that way.

Why people choose monogamy

For the calm of not having to negotiate.

The draw is in a whole category of questions falling away. Anyone who is exclusive does not have to decide every week what is allowed or weigh how a third person feels. And there is something in the idea itself: staying chosen, while the possibility of not being existed.

What monogamy gives differs per person:

• For you personally monogamy gives predictability: one relationship to put attention into, no second conversation about limits alongside the first.
• For your partner monogamy gives security, provided it has been said out loud. An assumption is not an agreement, and you only notice that difference when it goes wrong.
• For the two of you together monogamy gives time: what is not up for negotiation can go somewhere else.

Monogamy does not protect against boredom, and it does not heal anything either. Rutgers found that downside too. 56 percent of Dutch people are satisfied with their own sex life, and fewer than half with how often they have sex.

How people fill in monogamy in practice

Mostly serially: one partner at a time, several one after another.

Ryan Schacht and Karen Kramer lay out the evidence on human pair-bonding in Frontiers in Ecology and Evolution. Polygyny is permitted in most societies, but monogamy is the most common marriage form within every group. Sex outside marriage occurs everywhere, while the share of children not fathered by the steady partner is low in humans compared with socially monogamous birds and mammals. They call the pair bond a universal trait, one that most often shows up as serial monogamy.

In daily life you see three forms side by side. The silent one, in which nothing was ever agreed. The spoken one, in which a couple names what falls under it: only sex, or also flirting, porn, an old flame who texts. And the variant with one marked-off exception, like a festival or a birthday gift.

Careful or sloppy is not in the variant, but in whether you would both write down the same thing if asked separately.

Misconceptions about monogamy

“Monogamy is the natural state of humans.” Culturally it is more the exception: roughly 85 percent of the societies in the Ethnographic Atlas allow several women per man. What does seem universal is the pair bond, and that shows up, according to Schacht and Kramer, mostly serially.

“Being monogamous means you don’t desire anyone else.” Monogamy is about what you do, not what you think. A fantasy about someone else is no breach, unless the two of you have explicitly agreed it is.

“Anyone who isn’t monogamous is cheating.” That confuses two things. With cuckolding and hotwifing the partner knows and wants it; with cheating not. The difference is called consent.

What I see myself

I’m Victor, a gigolo, and I mostly see monogamy from the back end. The women who call me have often been monogamous for years without ever hearing what fell under that agreement.

The question “are we monogamous?” almost never gets asked, and “so what does that mean for us?” even less. Couples who come here together have had that conversation, and you can tell from how calm an evening like that runs. Couples where one arranged it and the other went along run into it the week after.

The second thing: the agreement rarely breaks on sex, but on the withholding. What happened is almost never the problem; that it was only told afterward, almost always.

What you can agree on with monogamy

• Say out loud that you are monogamous instead of assuming it. That conversation takes ten minutes and spares the most common source of pain here.
• Make a list separately of what does fall under it. Kissing, flirting, porn, contact with an ex, and lay the two lists side by side.
• Agree on what happens if something has happened: when you tell, to whom, and what holds in the first 24 hours after.
• Repeat the conversation when your life changes. After children, a move or an illness the old agreement often no longer fits.
• Don’t go along with something you don’t stand behind yourself. Joining in because your partner wants it is the outside-in motivation that, with hotwifing, links to worse outcomes.

More reading on monogamy

On this site, consent explains what agreement asks and boundary describes what you do when the agreement pinches. Anyone who wants to read the other side starts at cuckolding or compersion.

Beyond this site, the review by Schacht and Kramer is the best way into what is and is not scientifically settled about human pair-bonding. Henrich and colleagues also explain why exactly this form conquered the world.

Where this fits on this site

If you want to adjust the agreement together instead of letting it quietly fade, the page on a gigolo for couples covers what comes up in the first conversation and what gets set down in advance. If you come alone, just after a long relationship, sex after divorce is about the same question from the other side.

Sources

• The puzzle of monogamous marriage. Joseph Henrich, Robert Boyd & Peter J. Richerson, Philosophical Transactions of the Royal Society B 367(1589), 657–669, 2012 (DOI 10.1098/rstb.2011.0290). Review article in the journal of the Royal Society; the publisher page blocks automated access, so the full text was read via the first author’s publicly shared version and the link points to the PubMed record. Provides that roughly 85 percent of the societies in the anthropological record allow men to marry several women, that exclusive monogamy in the Ethnographic Atlas (1,231 societies) comes out at about 15 percent while polyandry stays under 1 percent, the ban years for polygyny in Japan (1880), China (1953), India (1955) and Nepal (1963), and the hypothesis that normative monogamy spread through advantage in competition between groups.
• Are We Monogamous? A Review of the Evolution of Pair-Bonding in Humans and Its Contemporary Variation Cross-Culturally. Ryan Schacht & Karen L. Kramer, Frontiers in Ecology and Evolution 7, article 230, 2019. Review of the literature on human pair-bonding. Provides that monogamy is the most common marriage form within every group even though polygyny is permitted in most societies, that sex outside marriage occurs everywhere while the share of children not fathered by the steady partner is low in humans compared with socially monogamous birds and mammals, and that the pair bond is a universal trait that most often shows up as serial monogamy.
• Civil Code Book 1, article 33. Dutch legislation, consulted via wetten.overheid.nl. Provides the literal text “A person can be joined in marriage with only one other person at a time”, the provision that makes marriage in the Netherlands monogamous.
• monogamie. Algemeen Nederlands Woordenboek, Dutch Language Institute. Provides the Dutch dictionary definition: a man or woman being married to or living with one partner, promising that partner faithfulness and keeping it as a way of life or rule, with “enkelvoudige echt” as an older term.
• Samenvatting Monitor Seksuele Gezondheid 2023. Rutgers, in cooperation with RIVM and CBS, 2024. Population study among more than fifteen thousand Dutch people aged 18 to 80, weighted to be representative. Provides that three-quarters have a steady partner, that 84 percent of that group want the relationship to be forever, that 56 percent are satisfied with their own sex life, and that fewer than half are satisfied with how often they have sex.

Related terms

• Consent. The agreement monogamy rests on, and what it takes to make it valid.
• Cuckolding. The best-known form of consensual non-monogamy, with the research to go with it.
• Hotwifing. The arrangement in which one partner sleeps with others, and what couples set down about it.
• Compersion. The feeling that would be the opposite of jealousy, and why it does not come on its own.
• Non-monogamist. The word for anyone who does not want the agreement, with the figures on how often that happens.
• Polyamory. The mirror image of this page: several love relationships at once, with the legal limit alongside.
• Swinging. The best-known departure couples agree on together, with the dating of the Dutch word.
• Boundary. Where you end up the moment the agreement no longer fits what you want.
• Ethical non-monogamy. The counterpole as a category, with the research that finds no difference in satisfaction.
• Affair. What happens when the agreement does hold and gets stepped outside of, with the figures on it.
• Ambiamorous. For anyone at home both here and in the counterpole, with the origin of that word.