Types of ethical non-monogamy, and how to tell which fits

Ethical non-monogamy covers any relationship style that is not exclusive, where everyone involved knows and agrees. The main types are open relationships, swinging, monogamish arrangements, the polyamory family (hierarchical, non-hierarchical, solo and closed) and relationship anarchy. They differ on a few plain questions: is it about sex, love or both, is there a central couple, and how much does everyone share? Your answers to those questions point to the style that fits.

What makes non-monogamy ethical

Consent, from everyone involved. The committee on consensual non-monogamy of the American Psychological Association's Division 44 describes these as relationships in which all partners give explicit consent to intimate, romantic or sexual relationships with more than one person, and says they are not to be confused with infidelity. Ethical non-monogamy and consensual non-monogamy are two names for the same family.

Everyone includes the people who arrive later. An agreement two people made before you met them still shapes your relationship with one of them. That is why a new partner has every right to ask what was agreed, and why the styles that keep someone in the dark are the ones that get argued about.

It is also less unusual than it can feel. In two US samples of single adults published in 2017, a little over one in five people (21.9 and 21.2 per cent) said they had been in a consensually non-monogamous relationship at some point, and gay, lesbian and bisexual people were more likely to say so. In a nationally representative Canadian survey of about 2,000 adults, 4 per cent of those in a relationship were in an open one, and 12 per cent called open relationships their ideal.

For trans and non-binary people, the one study we found puts the figure higher. Of 162 partnered trans and non-binary adults surveyed by Perez and Pepping in 2024, 32.1 per cent were in consensually non-monogamous relationships, and their relationship satisfaction did not differ from that of people in monogamous ones. The authors caution that most participants were white and non-binary, so the results may not hold for every group.

Open relationships, swinging and monogamish: a couple at the centre

These three styles usually start from a couple and decide what is allowed outside it. The edges blur, and the APA committee's fact sheet says plainly that its own definitions are broad and not mutually exclusive.

Open relationships

The fact sheet describes an open relationship as one where people are romantically exclusive with one partner while having other sexual partners, sometimes as a couple, sometimes independently. Others, including our glossary, use it more broadly to cover dating too. Day to day it can look like an ordinary couple's life with a few evenings that are not shared: one partner has a date on Thursday, and what gets said about it afterwards is whatever the two of them agreed.

Swinging

The fact sheet describes swingers as romantically exclusive with one partner and seeking other sexual relationships together, which can mean group sex or swapping partners with another couple. In interviews with 16 married swinger couples, the researchers Claire Kimberly and Jason Hans found that couples followed rules they had set together, and that communication, spoken and unspoken, was central to how satisfied they were. Unlike an open arrangement where each partner may go on separate dates, it is usually something the couple seeks out together.

Monogamish

Monogamish relationships are monogamous most of the time, with specific, agreed exceptions. The word is tied to the sex advice columnist Dan Savage, who described his marriage that way in a 2011 New York Times profile: occasional exceptions, which he and his husband are honest about. Day to day it looks like monogamy. The difference is that the exceptions are named in advance rather than discovered.

The polyamory family

Polyamory is about more than one relationship that matters, romantically as well as sexually. The APA fact sheet notes that polyamorous people may be single or partnered, and may be in a group of three or more or in several separate relationships. The styles inside it mostly differ on one question: does any relationship outrank the others?

Hierarchical and non-hierarchical

In hierarchical polyamory, one relationship is primary. A 2017 study of 1,308 polyamorous people recruited online describes a primary relationship as one where partners typically live together, share finances, are married if they want to be, or raise children, and a secondary one as usually living apart with separate finances. In that sample, primary relationships received more acceptance from family and friends and more investment and commitment; secondary ones involved more secrecy, and a larger share of their time together went on sex. Some hierarchies include a veto, where a primary partner can demand that another relationship end.

Non-hierarchical polyamory drops the ranking: no primary, no extra say over a partner's other relationships, and no veto, as the writer Kale Gossen puts it. That does not make every relationship identical. Someone can live with one partner and see another once a fortnight without either being structurally beneath the other.

Kitchen table, parallel and solo

Other words describe how a network behaves. In kitchen table polyamory, people are comfortable enough with their partners' other partners to sit down for coffee together. In parallel polyamory, relationships run side by side without overlapping, and those people may never meet. Solo polyamory is for people who do not want to merge their life with any partner: the writer Amy Gahran describes relationships with love, depth and commitment, but without exclusivity or merging such as living together or shared finances.

Polyfidelity

Polyfidelity is polyamory with the door closed: three or more people who are romantically and sexually exclusive with each other. The word comes from Kerista, a San Francisco commune that existed with changing membership from 1971 to 1991, where it meant closed, committed family units of up to a dozen lovers. A polyfidelitous group may stay closed or admit someone new with everyone's consent. Day to day it can look a lot like monogamy with more people at the table.

Relationship anarchy: no ranking at all

Relationship anarchy goes a step further. Andie Nordgren set it out in a Swedish pamphlet in 2006, later translated as The short instructional manifesto for relationship anarchy, which starts from the idea that love is abundant and every relationship is unique. Where non-hierarchical polyamory stops ranking romantic partners, Gossen writes, relationship anarchy rejects hierarchy across every relationship, friendships included.

Day to day, that can mean a close friend has as strong a claim on your weekend as a lover, and that nothing, from living together to sex to labels, is assumed because of what kind of relationship it is. Nordgren's manifesto asks people to customise their commitments and to change things through communication. In practice that tends to mean more conversation than a conventional relationship, not less.

Don't ask, don't tell, and the criticism it gets

In a don't ask, don't tell arrangement, often shortened to DADT, seeing other people is allowed but the details stay private. Zhana Vrangalova, writing on Feeld's website in 2023, sums up the deal: I don't ask what you do with others, and you keep it discreet so I don't find out by accident. The podcast Multiamory lists it next to parallel polyamory at the low end of what it calls a spectrum of entwinement, but as a separate thing: in parallel polyamory relationships simply do not overlap, while in DADT the details are deliberately not discussed.

People choose it for understandable reasons. Vrangalova lists not having to process a partner's experiences, the relief of out of sight, out of mind, and more energy for the rest of life, and says it can suit long-distance relationships. The site Non-Monogamy Help adds managing jealousy, and keeping a long shared life together as an alternative to separating.

It is also controversial in polyamorous communities, as Non-Monogamy Help notes. The site points out that when details are hidden it is hard to be sure everyone has given informed consent, especially around sexual health; that people dating someone in the arrangement can feel taken advantage of if nobody tells them; that it can look more like infidelity than openness; and that problems are harder to solve when the other relationships cannot be talked about. Vrangalova adds that it is hard to keep up without dishonesty, and may mean a partner is tolerating non-monogamy rather than wanting it. The therapist Wayne Scott, writing in Psychotherapy Networker, warns that it can lead to surprises that derail a relationship.

If you are the new person, you are owed at least one fact: that the arrangement exists.

Agreements versus rules

Every style above runs on agreements, and what they are called matters less than who got a say.

A distinction often drawn in polyamory writing, for example on the long-standing site More Than Two, separates rules from boundaries. A rule is something one person imposes on another. A boundary is something you set for yourself: not forbidding a partner to do something, but saying what you will do if they do it. The key difference, as the site puts it, is the locus of control. It is particularly critical of rules a couple writes before anyone new arrives, which can take things away from a third person who never agreed to them.

Agreements sit between the two: decisions made together by the people they affect. Jeff Levy, a psychotherapist in Chicago quoted in the same Psychotherapy Networker piece, says couples who do well have explicit agreements that answer key questions: what non-monogamy means to them, how they will handle disclosure, and what each does and does not want to know. The article notes that agreements often loosen as comfort grows. Marie Cacao, who counsels non-monogamous couples, puts less weight on formal agreements and more on understanding each other's fears, sensitivities and limits.

A few questions test any agreement:

• Did everyone it affects have a say, including partners who arrived later?
• Does it protect a feeling, or control a person?
• Is there a point at which you will look at it again?
• Would you be comfortable explaining it to someone new on a first date?

Which style fits, and how to say so

Nobody picks a style once and for all, but these questions narrow it down:

• Is it mostly about sex, about love, or both? Mostly sex points towards swinging, monogamish or many open arrangements; love points towards polyamory.
• Do you want a central partner whose life is merged with yours? If so, a couple-centred or hierarchical style may suit you. If not, look at non-hierarchical or solo polyamory.
• Do you want to know the details? If not, be honest about whether that is don't ask, don't tell, and what it asks of other people.
• Should partners meet each other? That is the kitchen table or parallel question.
• Should friendships carry the same weight as romance? Then relationship anarchy is worth reading about.
• Do you want the circle closed? That is polyfidelity.

Once you know, say it plainly. ENM on its own tells people the category, not the shape. In 2022 Hinge added an optional relationship type field offering monogamous, non-monogamous, or figuring out my relationship type; whatever an app offers, one clear sentence in your bio does more. Name the style, say whether you have partners now, and say what you are looking for. What to put on a dating profile covers the rest.

On a first date, the questions worth asking are the ones that affect you. Do you have partners, and do they know you are dating? Is anything agreed that would shape what this can become? What happens if it gets serious? Questions to ask on a first date has more. Someone's relationship structure is fair to ask about; their body is not.

Sexual health belongs in the conversation

Sexual health is one of the practical subjects non-monogamous people are expected to talk about, and research suggests many do. Summarising research by Conley and colleagues, the researcher Elisabeth Sheff wrote in Psychology Today in 2014 that openly non-monogamous people were more likely to get tested, to discuss their sexual health with partners, and to use condoms and other barriers than people who had not negotiated an open relationship. The APA committee's fact sheet likewise says people in consensually non-monogamous relationships report high levels of safer sex strategies.

Bedsider, a sexual health site run by the US organisation Power to Decide, calls openness about testing history and recent results a pillar of trust, and lists barrier use, scheduling and disclosure among the things to agree on out loud rather than assume. Questions worth raising with partners include:

• When did each of you last test, and how will you share results?
• Are barriers part of any agreement, and with whom?
• What changes when someone starts seeing someone new?
• Who else is connected, and who needs to know if something comes up?

This is a list of things to discuss, not medical advice. A sexual health clinic can tell you what testing and protection make sense for you and your partners.