Besides maybe period sex and who the best “Friends” character is, no subject is as hotly debated as whether or not flirting counts as cheating.

That’s because every relationship has different rules, so there’s no one-size-fits-all definition of cheating, says mental health professional Jor-El Caraballo M.Ed, a relationship expert and co-creator of Viva Wellness.

“Cheating is any behavior that a person takes that crosses and betrays a boundary of that specific relationship,” he says. For some folks that includes flirting, for some it doesn’t.

The swoony eyes and sustained eye contact. The arm graze and the body swivel. The knowing laugh and suggestive smirk. Most of us know a flirt when we see one (or are the one initiating).

What’s important to understand, according to Dr. Seth Meyers, licensed clinical psychologist and resident relationship expert for eharmony, is that not all flirts are created equal.

“They don’t all share the same motivation and emotional response to that flirting,” he says. Meaning, some flirt with the intention of more happening. Others do it just for fun, or as a form of self-expression.

It’s also important to understand what flirting isn’t.

Being nice to someone, giving someone else a compliment, or teasing them isn’t necessarily flirting.

Cue Yo Gotti’s “Down In the DM” because often it really does go down in the DMs. “Social media allows us to carry on a flirtationship or affairs from the comfort of your own couch,” says Caraballo.

But flirty DMs aren’t the only sign of cheating.

According to Caraballo, these examples may cross the boundaries of your relationship, and therefore qualify as cheating:

  • following someone you find attractive
  • commenting on that person’s posts
  • commenting or responding with certain emojis
  • engaging with frequency
  • watching someone’s Snaps or Insta stories
  • sending someone selfies

Some signs are obvious, others less so.

Your relationship is experiencing negative consequences

Whether online or offline, if your actions are affecting your relationship, it may be cheating.

Think: Your partner is feeling insecure in the relationship, or you’re going to someone else for emotional support instead of your partner.

You’re hiding that you have a partner

… or simply failing to mention it.

“If the person you’re flirting with doesn’t know you’re in a relationship, it’s tricky territory,” says Dr. Meyers. “It suggests that you might be open to something more substantial taking place in the future.”

Which isn’t just flirting. It’s flirting with the intention to cheat.

You’re acting or feeling like you have something to hide

“If you’re acting like you’ve got something to hide, you probably do,” says Caraballo.

Deleting texts or muting someone’s messages so your partner won’t see them? You’ve probably crossed the line.

The following feelings are also symptomatic of cheating behavior, Dr. Meyers says:

  • guilty
  • ashamed
  • secretive
  • angry at yourself (or the third party)
  • afraid
  • anxious
  • sad

If flirting is explicitly allowed in your relationship so long as it stays playful (and not emotional or physical), it’s kosher.

Key word: allowed. And the only way to know if flirting is allowed, or not? A conversation.

“It’s not as simple as asking someone if they want to be monogamous or polyamorous,” says Dr. Meyers. “You need to talk about what you each consider cheating — and whether flirting makes that list.”

So, if you and your partner establish that flirting is cheating, and you flirt, that’s cheating.

Likewise, if you’re in a polyamorous relationship and you and your partner agree that any flirting or physical conduct is OK as long as it’s not with anyone in your immediate friend group, and you flirt with someone in that group, that’s also cheating.

Start by being honest with yourself about what happened, and why.

If your flirting was premeditated or is indicative of a deeper dissatisfaction in your relationship, it may be time to cut ties.

If your flirting was just “you being you” (AKA you have a flirty personality), it may mean you’re not ready for the type of commitment your partner expects.

Or, you may need to establish new boundaries within your relationship that permits this behavior.

But if it was simply an “oops” and your partner would feel betrayed if they had been there or seen your flirty messages, it’s time to talk to them.

Telling your partner you flirted with someone else might be nerve wracking, says Jenni Skyler, PhD, LMFT, licensed marriage and family therapist for

“It’s the ultimate test of the strength of a relationship and your ability to communicate and compromise.”

Emphasize that you’re sorry, and explain how you will avoid making that mistake again, she says.

You may also have a conversation with the person you flirted with, or shut it down the next time it starts back up.

Some ways to talk to the person you flirted with:

  • “I want to apologize because I crossed a line during our last conversation. I want to let you know that while I enjoy your friendship, I’m in a committed relationship with someone I care for and won’t be flirty moving forward.”
  • “I know flirty banter has always been part of our dynamic, but I recently started seeing someone monogamously, so moving forward I’m not going to be flirty.”
  • “Hi! I had a great time talking with you on Friday, but I just want to let you know that I’m in a relationship and I’m sorry if my flirty behavior indicated otherwise. It won’t happen again.”

If the flirting happened on the web, an apology may need to be accompanied by hitting the block or mute button. Your — and your partner’s — call.

Have an honest conversation. Not necessarily about the flirting you may or may not have done, says Caraballo, “but about what the boundaries of your relationship are.”

Avoiding this conversation will only lead to future feelings of guilt, confusion, uncertainty, or worse.

Bring it up in a neutral environment (AKA some place outside the bedroom at some time that isn’t right after you had sex).

And understand that your partner could have any range of reactions — including being OK with flirting outside of the relationship and wanting to be able to flirt too, to wanting to end the relationship.

Some ways to bring it up:

  • “I really love spending time together and because I respect you and where this relationship is going. I’d love to talk about whether or not flirting with, kissing, or seeing other people is something we want to be able to do.”
  • “Yesterday, a barista at the coffee shop and I exchanged some flirty banter. And I’ve been feeling guilty because I’m not sure whether that’s allowed in our current relationship. Would you be open to having a conversation about boundaries?”
  • “We’ve been seeing each other for a few weeks, and we’ve never talked about what we’re looking for in a relationship. Are you looking for something exclusive?”

Bottom line: If you don’t know what the boundaries of your relationship are and you’re not sure what does and doesn’t constitute cheating, it’s time to establish them.

Here are some steps you can take to establish boundaries about what does and does not constitute cheating.

Do it early. Timing will vary, but usually somewhere between three and six months into the relationship is ideal.

Get specific. Is DM’ing someone socially that you’re attracted to OK? What about having a coffee alone with a coworker? Is it different if it’s dinner? Is texting an ex allowed?

Prepare to compromise. Different people have different personalities. If one partner’s personality is bubbly or charming, they may have to tune into where they’re directing that energy. If one partner is particularly jealous, they may need to do some self-work to course-correct that jealousy.

Plan for future check-ins. One convo usually isn’t enough, so make time a few months down the line to reconvene.

Whether flirting is cheating depends on the boundaries your relationship. That’s why establishing boundaries, sooner rather than later, should be a priority.

If you and your partner decide that flirting is cheating, it’s important that choice not be disrespected.

After all, while flirting may occupy some gray area on the “cheating” versus “not cheating” scale, boundary betrayal does not.

Gabrielle Kassel (she/her) is a queer sex educator and wellness journalist who is committed to helping people feel the best they can in their bodies. In addition to Healthline, her work has appeared in publications such as Shape, Cosmopolitan, Well+Good, Health, Self, Women’s Health, Greatist, and more! In her free time, Gabrielle can be found coaching CrossFit, reviewing pleasure products, hiking with her border collie, or recording episodes of the podcast she co-hosts called Bad In Bed. Follow her on Instagram @Gabriellekassel.