Here's What To Do If You're Fantasizing About Someone Else While In a Relationship

And when does it cross the line?
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Elizabeth Ayoola
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Elizabeth Ayoola
The Knot Contributor
  • Elizabeth contributes a range of lifestyle content to The Knot.
  • She also works as a full-time writer at NerdWallet and contributing writer at ESSENCE and POPSUGAR.
  • Elizabeth has a degree in Environment, Politics, and Globalization from King's College London.
Updated Feb 07, 2024

In most relationships there are spoken and unspoken expectations. Some revolve around simple things, like who should pay for dinner, and others are a bit more complex, like whether you can fantasize about other people. Inherently, fantasizing about someone else while in a relationship may be innocent since fantasies are simply thoughts. However, some people may characterize those thoughts as cheating, even if they never lead to any action.

There isn't a clear answer about whether it's acceptable to daydream about someone other than your partner, as it hinges on your values and boundaries. We spoke to Tyomi Morgan, a certified sexologist and pleasure coach, to provide more clarity about whether fantasizing is appropriate and when it crosses the line.

In this article:

Why Do We Fantasize About Someone Else While In A Relationship?

A fantasy is defined as imagining something that's improbable or unlikely to happen. Based on this definition, most of us have probably had these thoughts about people in romantic and non-romantic ways. For instance, you may fantasize about marrying your favorite celebrity crush or becoming best friends with your favorite celebrity.

Morgan says a reason people may fantasize about others is because the person they're fantasizing about has traits they desire, but they don't have access to them in real life.

"The only access that they have is in their own mind," Morgan says. "So they'll take the persona of that person, their qualities, their traits and then just daydream a little bit about them, which gives them the feeling of having an interaction with them, or even having a relationship with them, even though it's just a fantasy."

Fantasizing about someone else can also happen if someone isn't happy or sexually satisfied in their relationship. It's a form of escapism in that instance, Morgan says.

The type of fantasies a person has about someone else may also vary. For instance, it may be a sexual fantasy or one where the person imagines having a platonic relationship.

Is Fantasizing About Someone Else Cheating?

The answer to this question depends on the boundaries you've set in your relationship. Inherently, thinking about someone else isn't wrong and can be a healthy way to use your imagination, says Morgan.

"You're literally going within the safe space within your own mind and fantasizing about something that not only triggers a pleasure response, but it keeps the erotic fires going," she says. "It keeps the erotic imagination healthy, and it allows that person to exercise their creativity and their multifacetedness without compromising their relationship."

That said, not everyone sees fantasizing this way and some individuals may still see it as betrayal within a relationship. That may be the case if there haven't been prior discussions around expectations and boundaries. For this reason, it's important to discuss how fantasies may cross a boundary and when it's categorized as cheating.

Irrespective of boundaries put in place, it's important to ensure those boundaries don't cross over to control since our thoughts should be our own. Telling people what to think takes away their personal autonomy, which is a healthy part of any relationship.

"It is unhealthy to tell somebody you can't think about another person, you can't fantasize, because you're telling a person they can't be human," Morgan says.

Also keep in mind that conversations around boundaries and expectations aren't static–they should be revisited on a regular basis.

When Does Fantasizing Become Unhealthy?

Fantasizing about someone else may cross a boundary when it's getting in the way of your daily life or relationship with your partner. Here are some scenarios where fantasizing about someone else while in a relationship can raise a red flag.

Disconnects You From Your Partner

If fantasizing about someone else begins to get in the way of you connecting with your partner, it may be an issue. This could manifest as becoming withdrawn, an inability to sexually engage with your partner, not caring for your relationship responsibilities or relying on that fantasy for sexual fulfillment, says Morgan.

"When the fantasizing takes the place of their real life interactions with this person who they're in relationship with, and they say that they love and they're committed to, that's when it becomes unhealthy," she says.

Whether you're thinking about a crush or an ex, it shouldn't get in the way of you showing up in your current relationship.

Disrupts Your Daily Life

Fantasies often take you out of reality momentarily, which isn't necessarily a bad thing. Sometimes, we need a break from our reality or want to imagine something that feels better than what we're currently experiencing.

"The dopamine and the serotonin and the adrenaline that they get from fantasizing and having sources that they use to enhance their fantasizing can feel so good that they would rather escape into that world than to be in the real world," Morgan says.

However, if you're constantly living in the fantasy and not engaging with the present, that could prove to be unhealthy, she adds.

Crosses to Obsession

Fantasizing about someone else while in a relationship can become problematic when it shifts into the territory of obsession. If the lines between your fantasy and reality are becoming blurred and you spend the day preoccupied with someone else, it may be time to think about getting professional help.

How to Stop Fantasizing About Someone

If you're constantly fantasizing about someone else and you'd like it to stop, there are strategies that can help. Here are a few to consider.


Therapy or coaching can help if you're struggling with controlling your thoughts about others. For instance, if you can't stop fantasizing about getting back with your ex, it could indicate that you're struggling to detach from the relationship or the outcome you hoped for. A licensed therapist can help you process those emotions, find the root cause with the preoccupation, and give you tools for managing the fantasies.

Remove Reminders

Pay attention to when you fantasize the most. Is it after seeing an image of the person you're fantasizing about? When you hear certain songs? Or when you run into the person? If possible, remove reminders or things that feed your mind with images of them, says Morgan.

This can be done by unfollowing the person you're fantasizing on social media, deleting pictures of them and distancing yourself from any other elements that trigger the fantasy.

Communicate With Your Partner

If you're unhappy with your partner or sexually dissatisfied, a solution may be to have a chat with your partner. Communicating your needs and having them met could help minimize the fantasies. This isn't always an easy conversation to have, so if you feel stuck or like you don't know how to communicate your needs, consider a relationship coach.

Fantasizing about someone doesn't have to be a bad thing. Ultimately, being in a committed relationship doesn't mean you won't think about or be attracted to other people. The key is to communicate with your partner, pay attention if the thoughts begin disrupting your life.

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