Threesome

What is a threesome?

A threesome (Dutch: trio) is sex between three people at once, where at least one of them is physically, sexually active with both of the others. That last part is the dividing line: three people in one room busy two by two do not make a threesome. Who the third is and what happens is a separate matter.

What a threesome looks like in practice

The most common form is a couple with someone added, not three people who happen to run into each other. Arno Karlen described this back in 1988 in the first big academic work on the subject, Threesomes: Studies in Sex, Power, and Intimacy: a threesome usually consisted of a couple joined by a third person, women often saw it as a safe way to explore something of their own sexuality, and that third person was not automatically treated as an equal. It is summarized in the encyclopedia entry on threesomes.

So an ordinary evening starts weeks earlier, at the kitchen table: what happens and what does not, who starts where, and what counts as the moment one of the three has had enough. Only then comes the question of who the third will be. Turn that order around and you are negotiating limits with someone who is already in the room.

What the dictionary thinks of it

In Dutch, only something about music. The Woordenboek der Nederlandsche Taal, the historical dictionary of Dutch, lists one entry for TRIO with exactly one definition: “a piece of music for three instruments or three voices.” The Algemeen Nederlands Woordenboek does have an article, but it holds “no meaning profile (yet)” and gives only grammatical data: the word, plural trio’s, diminutive triootje.

The sexual meaning appears in neither, even though everyone knows it. What the ANW does give you is that diminutive, and that is exactly the word people reach for. Triootje sounds lighter than trio, and that difference does real work in a conversation where nobody wants to be the first to say it out loud.

Why people want a threesome

Because there is something to see that you normally never see: your own partner, from a little distance, with someone else. For the person joining without a partner, the pull is usually the opposite, all the attention at once.

How many people want it depends entirely on who you ask, and that is the most striking finding in the research. Ashley Thompson and E. Sandra Byers put the question in Archives of Sexual Behavior to 274 heterosexual students: 64% had some interest and 13% had done it, with 24% of the men against 8% of the women. The researchers noted that interest overall was low. Four years later the same researcher repeated it with a broader group, since students likely have less experience with this than older adults. Among 1,573 participants, 81% reported some interest and 30% had experienced it.

• For the couple, the gain is that something happened they can talk about together, instead of something one of them only fantasizes about alone.
• For the third, the gain is that nothing has to be kept going afterward.
• For no one is a threesome a repair. The numbers say most people are satisfied afterward, not that a threesome fixes something that was never said out loud.

Who the third is counts more than what happens

Both studies land on the same point: people would rather have a threesome with someone they know than with a stranger. In Thompson and Byers there is a skew in that worth writing down. For men it did not matter who the third was, as long as it was not a stranger. Women wanted someone familiar only when they were the third person themselves, and specifically not when it was their own partner joining in.

That is the knot couples get stuck on. Asking a friend along sounds safe and often is not, because she stays in your life afterward. A stranger feels more exciting and more risky. The third route is someone who does this more often and is gone again afterward.

What a threesome is not

“A threesome is the same as swinging.” Swinging is about a couple having sex together with others, usually with a second couple. A threesome only says how many people there are. Three single people who end up in bed together are not swinging.

“A threesome means two women and one man.” The notation MMF and FFM exists precisely because both forms occur. What happens beyond that is not fixed either: each participant can be active with one of the others or with both.

“If someone only watches, it counts as a threesome too.” That is where the line runs. Taking part without physical contact is read in the literature as voyeurism or cuckolding rather than as a threesome.

What I see myself

I am Victor, a gigolo and psychotherapist, and in this story I am usually the third. What I see is that a threesome rarely runs aground on what happens in the bedroom. It runs aground on something that was not said weeks earlier.

Most often it goes wrong on unequal desire. One really wants it, the other mostly wants the first to be happy, and that gap only shows once there is someone standing in the room. So I always ask each of them separately what they want, not the couple as a whole.

Something else stands out: most couples who call me have talked about it for years. The step itself is small, the conversation before it is the work.

What you can do

• Start with what you want to feel, not with what you want to do. “I want to be desired again with you there” is a conversation, “I want a threesome” is a proposal the other has to say yes or no to.
• Agree on what happens if one of the three wants to stop, before you invite a third. A safeword here applies to all three, so to the third person as well.
• Choose deliberately whether the third is someone from your circle. A friend stays in your life, and that is a choice, not a detail.
• Arrange consent with all three separately. Consent between you and your partner does not cover the third person.

More on threesomes

On this site, the practical side is in the guide on arranging a threesome with a gigolo, and the podcast interview on threesomes, swingers clubs, and spaghetti sex covers how it goes in practice. If you are wondering how it feels to watch your partner enjoy someone else, that word is compersion.

Beyond this site, the 2021 study by Thompson and colleagues gives the best overview of what people say about it, precisely because it surveyed older adults alongside students.

Where this fits on this site

If the thing you get stuck on is the question of who the third will be, that is exactly the role I fill. What happens then and in what order we set it down, from the first conversation to the evening itself, is on the page about couples.

Sources

• Heterosexual Young Adults’ Interest, Attitudes, and Experiences Related to Mixed-Gender, Multi-Person Sex. Ashley E. Thompson & E. Sandra Byers, Archives of Sexual Behavior 46(3), 813-822, 2017 (DOI 10.1007/s10508-016-0699-1; PMID 26943139; first names, volume, issue, and pagination checked against Crossref and against the PubMed record itself). Only the freely available abstract was used. Provides the 274 participants (202 women, 72 men), the 13% with experience (24% of the men against 8% of the women), the 64% with some interest, the note that interest overall was low, and the finding that men preferred someone familiar over a stranger regardless of the third’s status while women preferred someone familiar only for threesomes in which they were the third person themselves.
• Exploring Variations in North American Adults’ Attitudes, Interest, Experience, and Outcomes Related to Mixed-Gender Threesomes: A Replication and Extension. Ashley E. Thompson, Allison E. Cipriano, Kimberley M. Kirkeby, Delaney Wilder & Justin J. Lehmiller, Archives of Sexual Behavior 50(4), 1433-1448, 2021 (DOI 10.1007/s10508-020-01829-1; PMID 33175272; all five first names checked against Crossref). Only the abstract was read. Provides the two samples (231 students and 1,342 online participants, 1,573 people in total, of whom 907 heterosexual and 666 a sexual minority), the 81% with some interest, the 30% with experience, the preference for someone familiar over a stranger, the finding that participants on average said their experience met expectations, and the reason for the replication: earlier research was limited to students, who likely have less experience with this than older adults.
• TRIO. Woordenboek der Nederlandsche Taal via the Integrated Language Database of the Instituut voor de Nederlandse Taal, 10 August 2026. Returns one result and one hit: TRIO noun, “a piece of music for three instruments or three voices”. So there is no dictionary meaning of trio in which it is about sex.
• trio. Algemeen Nederlands Woordenboek, Instituut voor de Nederlandse Taal, 10 August 2026. Returns that the article holds “no meaning profile (yet)” and gives only grammatical data: neuter, the word, plural trio’s, diminutive triootje, collective noun.
• Threesome. Wikipedia. Provides the definition the article draws from Ryan Scoats (Understanding Threesomes, Routledge 2019), “a sexual interaction between three people whereby at least one engages in physical sexual behaviour with both the other individuals”; the notation MMF and FFM; the note that taking part without physical contact is read as voyeurism or cuckolding; and the summary of Arno Karlen’s Threesomes: Studies in Sex, Power, and Intimacy (1988) as the first big academic work on the subject, with the findings that a threesome usually consisted of a couple joined by a third, that women often saw it as a safe way to explore their sexuality, and that the third was not automatically treated as an equal. Written by volunteers; used here only for defining the concept and for summarizing two books that could not be read directly during this run.

Related terms

A threesome is the smallest form of sex with more than two people, and in terms of what you agree beforehand it sits closest to swinging.

• Swinging. The broader practice a threesome with a couple falls under, with the Dutch word history alongside it.
• Cuckolding. The form in which the partner watches instead of joining in.
• Hotwifing. The setup in which the third is there and the partner does not join in.
• Compersion. The name for what you hope to feel while you watch.