What’s cheating? Flirting with a stranger at a bar? Having lunch with your single co-worker? Kissing someone other than your partner? Men and women define it differently. We asked relationship experts to explain why. Plus, find out if you’re a likely two-timer with our quiz…

Years ago, I met a film critic who was in New York on assignment. He was married. I was not. There was an immediate spark. Drinks led to dinner and eventually back to his hotel room, where he was perfectly comfortable doing everything but. He drew the line at having sex. That, to him, was too far.

“It’s not cheating if we don’t have intercourse,” he said.

His wife probably would disagree, but I was struck by his definition of cheating.

Most people agree that it's bad, but the point at which flirting or idle curiosity becomes a betrayal is a gray area, particularly with laptops, BlackBerries and Facebook.

According to a 2007 MSNBC.com survey, about 22% of adults in monogamous relationships have cheated on their current partner. And nearly 50% of the 70,000 adults surveyed admitted being unfaithful at some point in their lives.

However, cheating didn’t always mean intercourse. Kissing, oral sex and online sex were also considered acts of infidelity by some.

In the era of instant messages, email, websites to help you stray (AshleyMadison.com) and phone texts, what’s the 21st century definition of cheating? If it’s all words and fantasy, does it count?
Real Life vs. OnlineRelationship experts pretty much agree that any sex-related behavior that might anger your partner could be called cheating.

But online or virtual cheating, in which people can be intimate, even sexual, though not necessarily physical, makes things murkier.

Take racy email exchanges, for example. They're fine, healthy even, according to Steve Santagati, author of The Manual: A True Bad Boy Explains How Men Think, Date, and Mate − and What Women Can Do to Come Out on Top (Random House).

He says he fields tons of suggestive emails (with pictures!) from women at his relationship advice website BadBoysFinishFirst.com.

“I’ll flirt back and say something naughty or provocative,” he says. And though he has a girlfriend, he doesn’t consider this to be out of bounds.

“That’s not cheating, it’s electronic,” he explains. Still, Santagati stops short at actual meetings.

“I don’t step over the line and say, Let’s hook up,” he says. “There has to be physical, sexual contact for the buzzer to go off and you’ve officially cheated.” 

But is that close enough to count?

Since cyber-sex is a relatively new social phenomenon, its language is still evolving, says Terri Orbuch, Ph.D., a scientist, marriage therapist and author of five relationship books.

“It’s not sex, but it is an affair. It is a betrayal,” she says. “Is it a sexual affair? I don’t know because the same kind of genital-genital or genital-mouth contact hasn’t occurred. The gray area is, Did I have a sexual affair because I had a sexual fantasy?”

Even if it’s all fantasy, it can have real-life consequences, as one of my guy friends found out when his wife stumbled onto the X-rated emails he was exchanging with an old girlfriend. No amount of explanation that nothing physical happened would convince her that he hadn’t actually cheated. She divorced him.

Same for another man whose girlfriend caught him in a virtual flirtation with someone else.

“She discovered the texts and felt horribly betrayed,” says Jack (whose last name was omitted, like others in this article, to protect his privacy). “She wished I had just slept with the girl," he says, because she felt the texting was more intimate and personal.

Virtual affairs let people dance close to the edge while still “rationalizing it because technically they haven’t touched another person,” says clinical psychologist Dennis Sugrue, Ph.D., co-author of Sex Matters For Women (Guilford Press).

“The problem is that anyone who thinks they have such absolute control over their emotions and desires is kidding themselves,” he says.

Even virtual relationships can evolve into something physical. After connecting emotionally online, it can be tempting to want to meet him or her in person. By some estimates, 31% of people end up having sex with someone they first connected with online.

“It becomes a very slippery slope,” Sugrue says.
The Gender GapThe MSNBC survey found that men and women have different standards for cheating: 89% of women said that kissing someone other than their partner was cheating; 77% of men agreed.

Sending a flirtatious email to a co-worker? It’s cheating, said 73% of women, compared to 53% of men.

Guys focus on whether their partners have done the deed with someone else.

But for women, a strong emotional connection to someone else is enough to qualify as infidelity.

For more on gender differences, check out 6 Reasons Why Women Cheat and 9 Reasons Why Men Cheat.

Those with a more permissive view of sex may not consider sexually or emotionally charged emails to be cheating, given that you’ve only exchanged thoughts and fantasies, not fluids.

So does that leave cheating in the eye of the beholder? Pretty much. Because rather than a one-size-fits-all definition of what constitutes cheating, it’s really more about the understanding you and your partner have, Sugrue says.

Not everyone draws the line in the same place.

For example, my friend Alicia’s husband says “the mere wish” of being with someone else qualifies as cheating. That would make adulterers of the thousands who fantasize about George Clooney or Angelina Jolie.

On the other hand, I also know another couple, married 17 years with two kids, who have an open marriage (aka consensual infidelity), which seems to work for them.

That's an extreme, of course, but most people fall somewhere in between. A stolen kiss with an ex-flame may be sinless for one person; a massage with a “happy ending” may be cheat-free for another.

Like my long-ago fling, you can rationalize all you like and split intellectual hairs about whether it is or isn’t cheating.

But as my friend Will, 35, puts it: “The precise semantics of who put what where (or didn’t) is just unnecessary detail. The big picture is, you breached your partner’s confidence.”

And that, relationship experts say, is probably the best gauge of whether you’re in questionable territory. If your partner would toss your stuff into the street and change the locks when they discovered what you’re up to, you’ve cheated.
Will You Cheat? Rate Your RiskAbout 55% of women and 60% of men cheat at some point during their marriages. While you can't always control what your partner does, how likely is it that you'll be the one to do the straying? Take our cheating quiz and find out!

Will He Cheat? Rate the Risk
It's thought that about 60% of men cheat on their partners - and 70% of wives don't have a clue. Is your guy ever-true... or a sneaky cheat? Take our cheating quiz to find out.

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