Linguistically, a lot has happened in the last 50 years when it comes to conversations about nonmonogamy.
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The terms ethical nonmonogamy and consensual nonmonogamy are both used to describe the same thing. In a nutshell, they refer to relationships that:
- involve more than two people, who
- all agree to the relationship structure.
The second part is what makes these non-traditional relationships ‘ethical’ or ‘consensual’. However, many people have raised a point of contention with the phrase ‘ethical nonmonogamy’.
Let’s explore why.
Where did ethical nonmonogamy come from?

Nonmonogamy has been around for as long as humans have. History is full of ancient evidence of harems, polygamy, affairs, and the like.
Of course, the term ‘ethical nonmonogamy’ wasn’t in use back then, and no one today is arguing about whether these arrangements were ethical.
To understand the current conversation around nonmonogamous relationships, we’ll need to fast forward a bit and bring things a little closer to home.
Language is cultural and evolves to meet the communication needs of the people using it. As I dug through recently written history on nonmonogamy, a few book titles stood out as major influences shaping modern language around nonmonogamy.
Open Marriage: A New Life Style for Couples, 1972
In the 1970s and on the heels of the sexual revolution, the term ‘open marriage’ came into broad use in the U.S. thanks to a popular book called Open Marriage: A New Life Style for Couples.
By the time the book was published, swinging was already a trend among married couples. One can only imagine that modern references to swinging as the ‘lifestyle’ have ties to this title.
Open marriages, and eventually open relationships, usually referred to partnerships where sex with other people was acceptable. These couples were still emotionally and romantically monogamous, and simply had sex with others outside of the relationship—or at least, that’s what popular writings of the time would have you think.
Certainly, plenty of people found themselves in arrangements of varying complexity and emotional depth. And of course, many non-cishet relationships likely featured nonmonogamy in ways that suited the partners involved, even if books weren’t written about it.
Love Without Limits: The Quest for Sustainable Intimate Relationships: Responsible Nonmonogamy, 1992
Twenty years later, Deborah Anapol published Love Without Limits. While it was less widely accepted than Open Marriage, it notably brought the phrase ‘responsible nonmonogamy’ to the public’s vocabulary.
Anapol’s perspective in this and later books differed from the ideas presented in Open Marriage. Rather than portraying extramarital sex as one option for increasing intimacy with your partner, she positioned nonmonogamy as a romantic or sexual orientation for many people. These people were capable of truly being in love with more than one person.
These people, she argued, are left to feel that they are ‘failing’ at relationships when really they are simply destined to fail at monogamy. In Love Without Limits and later books, she supports nonmonogamous people in their journey to love on their terms.
The Ethical Slut: A Practical Guide to Polyamory, Open Relationships, and Other Adventures, 1997
With ‘responsible nonmonogamy’ already in the lexicon, American polyamorists were primed to receive a controversially titled book that would knock things out of the park and change our language once again.
The word polyamory had already been in use since 1992. Five years later, The Ethical Slut hit shelves and quickly became known as ‘the polyamory Bible’. With its emphasis on ethical practices and honesty with all partners, it’s unsurprising that ‘responsible nonmonogamy’ gave way to the popular phrase, ‘ethical nonmonogamy’.
The Ethical Slut remains one of the most highly recommended books for new polyamorists and nonmonogamists of all kinds. The authors recently released a third edition with more inclusive language and highlights of important people in ethical nonmonogamy’s history.
What’s wrong with ethical nonmonogamy?

By the time I came across conversations about nonmonogamous relationships in blogs and forums in 2007, use of the term ‘ethical nonmonogamy’ seemed fairly straightforward. It was nonmonogamy that wasn’t cheating, an umbrella term that covered everything from polyamory to consensual cuckolding.
Cheating, of course, is understood to be unethical. It’s nonmonogamy without the consent of a partner. Cheating is deceptive, and exposes the unknowing partner to emotional and physical risk.
When someone said the word nonmonogamous in 2007, most people understood it to mean cheating. Ethical nonmonogamy, then, was the counter to that. ‘Cheating with permission’, or really not cheating at all.
Today, many people still use the phrase this way. Some people take issue with that.
What is ‘ethical’?

The main issue people bring up with the phrase ethical nonmonogamy is that defining what is ethical is, well, complicated.
Ethics vary from person to person, and situation to situation. On top of that, both people and situations change. As a result, it’s impossible to hammer down a truly static and completely agreed-upon understanding of what constitutes ethical vs. unethical practices in nonmonogamy.
For example, say a hypothetical person named Alex agrees to open a relationship sexually, but not emotionally. As sometimes happens, Alex later falls in love with one of their sexual partners.
- Is Alex ethically wrong for falling in love with a second person?
- Is Alex ethically wrong for not knowing that falling in love was a possibility?
- Was Alex ethically wrong for agreeing to a relationship that was only open sexually?
- Is anyone who opens their relationship ‘only sexually’ ethically wrong?
- Would Alex be ethically wrong for wanting to continue their relationships with both romantic partners?
- Would Alex be ethically wrong for asking to continue both relationships?
- Would Alex be ethically wrong for ending one or both relationships now that love is a factor?
- Would Alex have been ethically wrong for ending any sexual-only relationships that distracted from their primary romantic relationship?
- What about Alex’s partners’ (each of them) ethics in all this?
I could keep going, but I’m sure you get the point. The answers to these questions are all subjective. What even is ethics when it comes to love and autonomy?
Other arguments against the phrase ethical nonmonogamy include that:
- consent shouldn’t be the only thing determining whether something is ethical
- nonmonogamy works just as well as an umbrella term since ethics are too conditional to agree on
- though ethical nonmonogamy refers to all forms of consensual nonmonogamy, people often mistake it for a separate practice that is somehow better than polyamory, swinging, open relationships, etc.
The Rise of Consensual Nonmonogamy

As a response to the issues with ethical nonmonogamy as a phrase, many people have begun substituting the term consensual nonmonogamy.
Consensual nonmonogamy isn’t a new phrase, but it is new compared to others in this post. The first evidence I can find of its use is in a 2006 research paper on women’s sexuality.
The term appears to have stayed confined to academia for a while. But by 2018, books like Swingers’ Little Helper and A Therapist’s Guide to Consensual Nonmonogamy were racking up sales and recommendations on Amazon with consensual nonmonogamy right on their covers:
So What Are We Supposed to Say?

I have to admit, consensual nonmonogamy is probably a more honest description of nonmonogamy that isn’t cheating. At the same time, the more we dig into consent, the more we recognize that it, too, is an amorphous thing defined differently by different people.
Perhaps in time, this phrase too will go out of style and give way to something even better.
Or maybe we’ll drop the qualifier altogether. An increasing number of people are doing this already, simply saying ‘nonmonogamy’ and refusing to distinguish themselves from cheaters. Cheating is an ethical issue, after all, and ethics are fluid.
While we wait to see what the future holds, both ethical nonmonogamy and consensual nonmonogamy appear to be understood by most people talking about alternative relationship styles. I think you should use whatever phrase works for you. As long as you’re treating your partners with respect, I won’t nitpick vocabulary.
Ah, respectful nonmonogamy. Now there’s an idea.

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