Ethical non-monogamy, explained

"Ethical non-monogamy" (often shortened to ENM) is an umbrella term, not a single relationship style. It covers several different structures that share one thing in common: everyone involved knows about and has agreed to the arrangement. That's also the entire distinction between ENM and cheating — not the number of partners, but whether everyone consented to the terms.

The one thing that makes it "ethical"

Cheating is defined by broken trust: an agreement (usually monogamy) is violated without a partner's knowledge or consent. Ethical non-monogamy removes that agreement by mutual consent instead of breaking it in secret. That's the whole definition — it says nothing about how many partners someone has, how casual or serious those connections are, or how the relationship is structured beyond "everyone agreed to this."

Open relationships

A primary couple (or, less commonly, a group) agrees that one or both partners can have sexual or romantic connections outside the relationship, under terms they've set together. Terms vary widely — some couples set rules about disclosure, safer-sex practices, or which activities are in or out of bounds; others keep things looser. The core relationship stays the reference point.

Polyamory

Poly relationships are built around the possibility of multiple simultaneous romantic relationships, not just sexual ones — the emotional connection is the point, not a side effect. Structures vary: some polyamorous people have one "primary" partner and other secondary relationships; others (practicing "relationship anarchy," see below) reject ranking partners at all. Poly relationships can include people dating multiple partners individually, or interconnected groups sometimes called polycules.

Swinging

Swinging is generally the most structure-focused of the three: a couple engages in sexual activity with other people or couples, usually together and usually without the expectation of ongoing romantic attachment to those outside partners. It's often organized around specific events, parties, or clubs — see our guide to visiting a sex club if that's the specific context you're curious about.

Relationship anarchy

A less common but distinct approach: relationship anarchy rejects the idea that romantic relationships should automatically outrank friendships in importance or commitment. Instead of a hierarchy with a "primary" partner at the top, each relationship is defined individually by the people in it, without a default set of rules borrowed from the traditional relationship escalator.

How common is this, actually?

A nationally representative 2017 survey of Canadian adults found real, measurable prevalence — a small minority currently practicing it, but a much larger share who'd tried it or find it appealing:

The same study found no significant difference in relationship satisfaction between people in open relationships and people in monogamous ones. See the full breakdown, including the partnered-specific figure, in our Canadian open relationship stats.