Is an Open Relationship Cheating?

By the Rope & Candy team · · Open Relationships

No, an open relationship is not cheating, as long as both partners freely agree to it and keep to what they agreed. Cheating is about deception: breaking the promises a relationship rests on, usually in secret. In an open relationship, the promise itself is different, and everything happens with both people knowing. Openness only turns into cheating when someone breaks the agreement or hides things they promised to share.

That is the short version. The longer version is worth reading if you are thinking about opening up, or if someone in your life has just told you they are open and you are not sure what to make of it.

What cheating actually is

Ask ten people to define cheating and you will hear ten answers. Some say any sexual contact with someone else. Some include emotional affairs, secret messaging or even certain kinds of flirting. What almost every definition shares is this: cheating is a broken promise, kept hidden from the person it was made to.

Notice that this is about agreement and honesty, not about sex itself. A monogamous couple who promised each other exclusivity are cheating if one of them has a secret affair. An open couple who agreed that outside connections are fine, and who tell each other as agreed, are not.

It also helps to remember that every couple sets its own line, open or not. Some monogamous couples are fine with flirting at parties, others count a secret dating app as betrayal. Open couples simply draw their line in a different place, and say it out loud. The test is the same for everyone: did you keep the promise you made?

This is why researchers and the people who live this way talk about consensual or ethical non-monogamy. The word "consensual" is doing the heavy lifting. A 2017 study by Haupert and colleagues found that about one in five single US adults had been in a consensually non-monogamous relationship at some point, and the studies take care to separate those relationships from infidelity, because the experience is so different.

In an honest open relationship:

  • Both partners know the relationship is open
  • Both agreed freely, not under pressure
  • They have shared agreements about what is fine and what is not
  • They tell each other what they agreed to tell

When all of that is true, there is nobody being deceived. You can like or dislike the idea, but it is not cheating. Our guide to consensual non-monogamy explains the different forms it can take.

Yes, you can still cheat in an open relationship

This surprises people, but it is true. Open relationships have promises too, and breaking them hurts just as much. Examples:

  • Seeing someone who was agreed to be off-limits, like a close friend or a colleague
  • Skipping safer sex when you agreed not to
  • Not mentioning a new connection when you agreed to say
  • Lying about where you were, or who with
  • Quietly letting feelings grow when you agreed to talk about them early

Many open couples say the betrayal in these moments is not the act itself. It is the secrecy. That is why clear, shared open relationship rules matter so much: they define what cheating means for the two of you.

When "open" is used as cover

Sometimes people do misuse the idea. Two common patterns:

  1. Opening up after the fact. Someone is already having an affair and proposes openness to make it acceptable. The partner is being asked to approve something that has already happened, often without knowing it.
  2. Opening up under pressure. One partner keeps asking until the other gives in. That is not a free yes.

Both of these mix openness with deception or pressure, and both tend to end badly. Our piece on why some open relationships fail goes into this. If you are thinking of raising the idea yourself, our guide on how to ask for an open relationship shows how to do it honestly.

This is general information, not legal advice. Across the US, Canada, the UK and the EU, sex between consenting adults is a private matter. What is illegal everywhere in these places is bigamy, meaning being legally married to more than one person at the same time. A few US states still have old adultery laws on their books, which are rarely enforced, and New York repealed its own in 2024. If adultery could matter in a divorce or custody case where you live, talk to a local lawyer.

What about how other people see it?

Family, friends, religious communities and coworkers may still call it cheating. That is their view, and you do not have to argue with it. Some open couples tell nobody. Some tell a few trusted friends. If you decide to talk about it, our guide to explaining non-monogamy to friends and family has calm, simple ways to put it.

A line many couples find useful: "We have made different agreements from most couples. We are honest with each other about everything. It works for us."

An invented example

Hannah and Joe had been open for two years, with an agreement to always tell each other before meeting someone new. One evening Joe met a woman he had been chatting with and mentioned it only a week later. Nothing he did that night was outside their rules, apart from the timing. Hannah still felt cheated on, and she was right to: the promise he broke was the telling. They talked it through, he apologised without excuses, and they agreed that "before" meant before, not "soon after". Their relationship is still open, and the trust came back because he owned it.

Honesty is the whole point

The heart of an open relationship is not freedom. It is honesty: saying what you want, agreeing together, and keeping your word. Do that, and you are not cheating. You are doing something many monogamous couples never manage, which is talking openly about desire.

If you are both on board and would like to meet open-minded couples and single women in a discreet circle of friends, over a coffee or a dinner first, you can join Rope & Candy. It is free, and nothing is ever expected of you.

Questions people ask

Is it cheating if my partner agreed to an open relationship?

No. Cheating means breaking the promises a relationship is built on, usually in secret. If you both freely agreed to an open relationship and you keep to what you agreed, nobody is being deceived, so it is not cheating.

Can you cheat in an open relationship?

Yes. If you break an agreement, hide something you promised to share, or see someone who was off-limits, that is a breach of trust, and many open couples would call it cheating. The rules are different, but the idea of keeping your word is the same.

Is an open relationship just an excuse to cheat?

It can be misused that way, for example when someone pushes a reluctant partner into it to justify what they already want. Done honestly, though, it is the opposite of cheating, because everything happens with both partners knowing and agreeing.

Is adultery illegal if we have an open marriage?

In most of the US, Canada, the UK and the EU, sex between consenting adults is not a crime. A few US states still have old adultery laws on their books, though New York repealed its own in 2024. This is general information, not legal advice.