ENM (ethical non-monogamy)

ENM stands for ethical non-monogamy, an umbrella for relationships where everyone involved knows and agrees. Researchers say CNM, consensual non-monogamy. Hinge and Tinder made non-monogamy a profile option in 2022 and 2023. How common it is depends on what you count: 34% of 1,000 US adult citizens polled by YouGov in 2023 called their ideal something other than complete monogamy.

Updated October 6, 2026

Means

Non-monogamy that everyone involved knows about and has agreed to

First seen

'Polyamory' proposed on Usenet in 1992 (alt.polyamory; Merriam-Webster dates it to 1992); 'consensual non-monogamy' in research from the 1990s and 'ethical non-monogamy' later (Cardoso, 2024); 'ENM' on Urban Dictionary June 28, 2018; Dictionary.com lists 'ethical non-monogamy'; no entry for 'ENM' in Dictionary.com, Merriam-Webster, Cambridge or Collins as of October 6, 2026

Related terms

Open relationship, Casual dating, Friends with benefits (FWB), Roster dating, DTR (define the relationship)

ENM, ethical non-monogamy, is non-monogamy that everyone involved knows about and has agreed to. Researchers tend to write CNM, consensual non-monogamy, instead, and our reading is that consent can be checked, while ethics is a claim. On a dating profile, ENM is a disclosure rather than a description, and the types table shows how much three letters can cover.

What ENM means, and ENM vs CNM

Dictionary.com defines ethical non-monogamy as “the practice of having or pursuing more than one sexual, romantic, or marital relationship at a time, with the awareness and consent of all partners” (Dictionary.com). The abbreviation is less settled. We found no entry for ENM in Dictionary.com, Merriam-Webster, Cambridge or Collins on October 6, 2026. Cambridge has non-monogamy, and Merriam-Webster and Collins only nonmonogamous. Those three pages would not load for us, so we read them in search results (Cambridge Dictionary; Merriam-Webster; Collins). Wiktionary does list ENM, with its earliest quotation from The Guardian in 2024 (Wiktionary).

The research term is the older one. In a 2024 paper on the two names, Daniel Cardoso reports “very early traces of CNM in the 1990s without any such equivalent for ENM.” Communities later shifted to ENM, which, he writes, “has generated the notion that ENM arose first and CNM was created in response to it, rather than the (empirically verifiable) opposite.” Researchers wanted a wider word than polyamory, which was “insufficiently encompassing of other forms of relating that were also in tension with mononormativity,” the assumption that monogamy is the norm. And “consensual” was the “analytical gesture of boundary-keeping used by researchers to demarcate their work from work on ‘cheating’ or ‘infidelity’” (Cardoso, 2024).

Polyamory was proposed on Usenet. Jennifer Wesp set up alt.polyamory in 1992 and “didn’t want to use a hyphenated negation to describe something positive, and so advanced ‘poly-amory’ as a proposal” (Cardoso, 2024). Merriam-Webster dates the word to 1992 (Merriam-Webster). “Ethical” was on a book cover by 1997: The Ethical Slut, by Dossie Easton and Janet Hardy, subtitled “A Guide to Infinite Sexual Possibilities,” from Greenery Press, with a third edition from Ten Speed Press on August 15, 2017 (Wikipedia). We found no source saying the book coined the phrase.

Urban Dictionary got the abbreviation with a mix-up attached. The earliest entry we found using ENM this way, from June 28, 2018, reads: “Stands for Ethical Non-Monogamy. Otherwise known as swinging.” An entry from December 25, 2019 has “A style of relationship where non-monogamy…is practiced in a ethical/moral fashion” (sic) (Urban Dictionary).

None of that history reaches the profile. There, the letters say the monogamous default is off. They do not say whether there is a partner, whether the partner knows, or what is on offer.

Types of ENM: open relationship, polyamory, swinging and more

ENM is the umbrella, and the arrangements below sit under it. The table is our simplification; people name their own arrangements.

Polyamory has a page of its own, with the word’s history, its vocabulary and the US city laws; here it gets a paragraph. Moors, Gesselman and Garcia describe it as “a distinct type of consensually non-monogamous relationship where people typically engage in romantic love and sexual intimacy with multiple partners” (Moors et al., 2021). The weight is on relationships. An open relationship usually keeps one couple at the center.

Two rows have a known origin. Monogamish is Dan Savage’s term, popularized in 2011 by a New York Times Magazine profile by Mark Oppenheimer, “Married, With Infidelities,” published online June 30, 2011 (Oppenheimer, 2011). The earliest relationship anarchy text we found is Swedish. Andie Nordgren’s manifesto was “originally published in Swedish as ‘Relationsanarki i 8 punkter’ by Interacting Arts in 2006” (Nordgren, 2006).

What does ENM mean on dating apps?

On the big apps, ENM is now a menu option, worded differently on each. Hinge says “non-monogamous”; Tinder and Bumble say ethical non-monogamy.

The fields work differently too. Hinge counts relationship type among the preferences that “help guide the people you’re most likely to see” (Hinge). Tinder’s announcement says the choice is “added and displayed on their profile” and mentions no filter, so on Tinder it shows on the profile (Tinder, 2023).

The apps have numbers of their own, and all of them are company data. OnePoll surveyed 4,000 actively dating singles aged 18 to 25 for Tinder, 1,000 each in the US, UK, Australia and Canada, from January 21 to February 7, 2023. Tinder reports that “41% of them are open to or seeking non-monogamous relationships” and we found no method beyond that (Tinder, 2023). TechCrunch, citing the BBC on November 16, 2022, reported that one in five Hinge users “would consider” an open relationship and that one in 10 had already tried one; we found no sample size or survey date (TechCrunch, 2022). Feeld’s “Open Invitation” survey was designed by Amy Moors of Chapman University and the Kinsey Institute with Multiamory and OPEN, and “received nearly 6,000 responses, with 42% coming from Feeld members.” Of the respondents who use dating apps, 70% were “exploring as individuals,” and “only 11% of ENM daters are looking for couples” (Feeld, 2026). Respondents reached the survey through Feeld and ENM organizations, so they chose to take part.

On Mumsnet, a British parenting forum, a thread titled “Ethical non monogamy WTF?” was started on December 27, 2024 and has about 197 replies. The poster, back on the apps, was seeing ENM or polyamorous on one in six or seven of the profiles she saw, by her count. One reply: “Better that they say it up front than pretending to be monogamous and cheating.” Another: “The sort where everyone involved knows about it and is ok about it is the ethical sort” (Mumsnet, December 2024). In a thread started January 16, 2025 (about 84 replies), one reply said: “It’s not an open relationship because that has to be agreed by both partners” (Mumsnet, January 2025).

Is ENM cheating? What to do about it

ENM is not cheating, because everyone involved agreed to it. The deal can still be broken, and the research and survey figures on that are under can you cheat in an open relationship.

On The Student Room, a UK student forum, a thread titled “Why don’t people like polyamory?” was started on June 18, 2021 and drew 34 replies. One reply told the poster that “the example you’ve given doesn’t sound like a polyamorous relationship. It sounds more like casual hook-ups,” and added: “Polyamorous relationships still require a commitment but just with multiple people” (The Student Room, June 2021). In a Mumsnet thread titled “ENM,” started November 3, 2023 (about 17 replies), one post put it as “ENM is about 80% communication and 20% sex” (Mumsnet, November 2023). That is one poster’s estimate, not a measurement.

Our steps, not a study’s:

1. Ask what it looks like in an ordinary week. Everything in the types table fits under the same three letters. One of ours, not tested at scale: “Your profile says ENM. I’d like to hear what that looks like in an ordinary week.”
2. Ask whether there is a partner, and whether the partner knows. Two of the Mumsnet replies above made the same point: it counts as ENM only if everyone involved knows.
3. If you want monogamy, say so in the fields early. Set relationship type on Hinge or Tinder, or pick a Bumble badge, before the first message. The field says it for you, so it does not have to come up on a third date.
4. If a partner asks to open the relationship, treat it as a change to the deal. What to weigh is on open relationship, and the conversation works like a DTR: say where you stand, then listen.

How common is ENM? What the research says

These are surveys from the US and Canada about status and attitudes, and none of them looked at a dating profile. They measure five different things.

YouGov’s ideal question uses a scale from 0, “complete monogamy,” to 6, “complete non-monogamy” (YouGov, 2020). Our reading: when a page quotes one number for how common ENM is, check which row it came from. The figures run from 2.4% to 34% because they answer different questions.

On how these relationships go, a 2017 review by Conley, Matsick, Moors and Ziegler reported “few differences in relationship functioning” between people in monogamous and CNM relationships, in research that relied on online convenience samples (Conley et al., 2017). We read the abstract in a search result. That is as far as the finding goes: similar on the measures used, not better or worse.

Every sample here is from the US or Canada, and much of the CNM research relies on people who chose to answer. We found no UK or Swedish prevalence survey.