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What’s an Affair? Defining Infidelity

Six women are seated around a living room table sipping merlot when the topic of infidelity surfaces. Each one has a different definition of cheating.

“Infidelity begins when you overtly flirt with someone,” says the first.

“I think cheating happens when you kiss … with tongue,” another chimes in.

“What about an affair?” a third asks. “What qualifies as one?”

“Sex,” two of them say out loud.

“Just intercourse or does oral sex count?” another asks.

Rethinking infidelity

This conversation represents the confusion associated with the word affair. I used to reserve the term only for relationships that passed the boundary into sexual intercourse, but that changed after watching a Ted Talk by affair expert Esther Perel called “Rethinking Infidelity: A Talk for Anyone Who Has Ever Loved.”

“Infidelity,” she explains, “includes one or more of these three constitutive elements: secrecy, sexual alchemy, and emotional involvement.” Perel expounds on the three elements in her bestselling book, The State of Affairs.

The seduction of secrecy

“Secrecy,” she writes, “is the number one organizing principle of infidelity. An affair always lives in the shadow of the primary relationship hoping never to be discovered. The secrecy is precisely what intensifies the relationship.” Secrecy can be an indirect and albeit dangerous way of securing autonomy and control.

Affairs are a space where a person feels as though he or she can define the rules, according to Perel. The forbidden relationship provides a false sense of empowerment that is intoxicating.

Replacing sex with eroticism

Sexual alchemy is the term that Perel uses in place of sex, because she prefers a definition of sexuality that is more expansive, one that encompasses more than sexual acts. Sexual alchemy includes “a broader understanding of the erotic mind, body, and energy.” According to Perel, “affairs sometimes involve sex and sometimes not, but they are always erotic.”

Based on her work with countless couples, she asserts that affairs are often less about sex than about desire … “the desire to feel desired, to feel special, to be seen and connected, to compel attention. All these carry an erotic frisson that makes us feel alive, renewed, recharged. It is more energy than act, more enchantment than intercourse.”

Where does cheating begin?

This is a thorny issue that goes back to the debate among the six women. If we judge an affair by the level of eroticism, it’s possible that an imaginary kiss could be more exciting than hours of intercourse. Does that, then, mean our sexual fantasies make us cheaters? According to Perel, couples must define that for themselves. She writes, “Even if we agree to widen the lens to include a variety of sexual expressions, we may still disagree about what they mean and where they belong… Every couple has to negotiate each other’s erotic independence as part of the larger conversation about our individuality and our connection.”

That’s not a green light to experience eroticism however we want. There has to be a level of transparency in our relationships. Committing to brutal honesty within a partnership can protect us, to a certain degree, from betrayal.

Emotional connection

Finally, all affairs involve varying degrees of emotional connection. Forbidden love stories like the ones depicted in The English Patient and The Bridges of Madison County involve a kind of awakening or transcendence, a coming to life that feels pure or destined by fate. Other connections are less intense, but still involve an emotional bond that is invigorating and comforting.

What’s the greater betrayal?

Consider two scenarios. In the first, your partner has too many cocktails at a company happy hour and ends up sleeping with his co-worker. He assures you it was a one-night stand that didn’t mean anything. In the second, he has developed a strong emotional attachment to his co-worker, but has not been physical in any way. Which is the greater betrayal?

Although this question has been debated over and over again, it is still fraught with questions and curiosities. Perel explains:

Our individual sensitivities are idiosyncratic. Some people aren’t bothered by emotional attachments to others, so long as they keep their hands to themselves. Others don’t see sex as a big deal and give each other freedom to play—as long as there are no feelings involved. They call it “emotional monogamy.” For most of us, sex and emotions are difficult to untangle. You can have a lot of each, more of one, or more the other, but they are usually both at play in the adulterous sandbox.

In other words, she says, our definitions of infidelity are shaped by our individual beliefs and by the stories we tell ourselves. Undoubtedly our beliefs and stories change over time.

A complicated matter

That’s certainly true for me. For much of my life, I approached the topic of infidelity with my typical Vatican, black-and-white thinking: kissing and all forms of sex outside a marriage are deadly sins. However, seeing good people stray from their marriages has expanded my view and extended some compassion, not only to the betrayed but also to the betrayer. I now see affairs as a much more complicated matter, as a behavior sometimes driven by unresolved pain and trauma rather than actions intended to hurt a spouse. Not only are the reasons behind cheating muddied, so too are the categories of infidelity.

So what is an affair?

I agree with Perel that each couple has to define for themselves what consists of one and what doesn’t. It’s true, too, that complete transparency between two committed partners can both protect them from betrayal and heal the rupture caused by infidelity.

What do you think? What constitutes an affair?

What’s an Affair? Defining Infidelity

Therese J. Borchard

Therese J. Borchard is a mental health writer and advocate. She is the founder of the online depression communities Project Hope & Beyond and Group Beyond Blue, and is the author of Beyond Blue: Surviving Depression & Anxiety and Making the Most of Bad Genes and The Pocket Therapist. You can reach her at or on Facebook, Twitter, Instagram, or LinkedIn.

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APA Reference
Borchard, T. (2019). What’s an Affair? Defining Infidelity. Psych Central. Retrieved on October 28, 2020, from
Scientifically Reviewed
Last updated: 8 Mar 2019 (Originally: 3 Mar 2019)
Last reviewed: By a member of our scientific advisory board on 8 Mar 2019
Published on Psych All rights reserved.