What counts as cheating? Where most people draw the line

Updated October 6, 2026 · 14 min read

Cheating is breaking the deal you have with a partner. Most people's default puts sex and kissing over the line and porn under it, and the middle moves with how a survey asks and what a couple agreed. Below: surveys from 2014 to 2026 act by act, why open couples can cheat too, and the little the law says.

What counts as cheating comes down to the agreement you have with a partner, whether anyone said it out loud or not. Most couples never spell theirs out, so they run on a default, and surveys show its shape: sex and kissing at the top, porn and strip clubs near the bottom, and a middle that moves with the answer options a survey offers. If you have not agreed to be exclusive with anyone yet, most of what follows breaks nothing.

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What counts as cheating, act by act

The surveys below asked adults what they would count, not couples about each other.

• YouGov US 2022: about 2,000 US adult citizens on an opt-in panel, September 15 to 22, 2022, published October 4, 2022. Yes or no, about “a person who is in a monogamous relationship” (YouGov, 2022).
• Deseret News US 2017: commissioned by the newspaper, questionnaire by Y2 Analytics, 1,000 US adults on YouGov’s panel, released April 12, 2017. Always, sometimes or never “cheating on a spouse or partner” (Deseret News, 2017).
• YouGov UK 2026: 1,882 Britons, July 9 to 10, 2026, published August 17, 2026. Cheating, harmless, or a middle option, “while this behaviour is not harmless, it is not actively cheating” (YouGov, 2026a; YouGov, 2026b).
• Kinsey Institute and DatingAdvice.com US 2025: the “State of Us” study led by Justin Lehmiller and Amanda Gesselman, 2,000 single US adults aged 18 to 91, online, data collected by Prodege from April 29 to May 8, 2025. DatingAdvice.com is a dating-advice website that co-published the study with the Kinsey Institute. Respondents answered about relationships in general; we use the figures as Lehmiller reports them and did not see the answer options (DatingAdvice.com, 2025; Lehmiller, 2025).
• YouGov US 2014: a poll published May 17, 2014, giving the share who called each act cheating; sample size not given on the page (YouGov, 2014).
• iFidelity US 2019: the National Marriage Project with the Wheatley Institution, fielded by YouGov, 2,000 US adults asked about acts done “without your knowledge or consent”, answering unfaithful, not unfaithful or depends. We read its figures from the report’s chart (National Marriage Project, 2019).

Share calling each act cheating, by survey. Different countries, years and answer options; read across a row, not down a column.

The last column is our summary of the threads and surveys on this page, not a finding. A blank cell means the survey did not ask, or the results we read do not show it.

The answer options move the middle. Asked yes or no, 81% of US adults in 2022 called kissing someone else cheating (YouGov, 2022). Given a middle option, 73% of Britons in 2026 did and 16% chose the middle (YouGov, 2026b). With always, sometimes or never, 71% of US adults in 2017 said always and 11% sometimes (Deseret News, 2017). Flirting falls further, from 55% in the 2022 YouGov US yes-or-no poll to 26% in the 2026 YouGov UK survey, as the micro-cheating scale shows. Different countries, years and wordings: a pattern, not a trend. The middle option is where a couple’s own agreement matters most.

Advice pages often sort cheating into types instead, usually some mix of physical, emotional, online, financial and micro-cheating, and the count varies by site. The groupings researchers use are on micro-cheating, and the hidden bond has its own page, emotional cheating.

Is kissing cheating?

For most people in a monogamous relationship, yes. The 2017 Deseret News survey split “romantically kissing someone other than your partner” into 71% always, 11% sometimes and 18% never (Deseret News, 2017), and 70% of the US singles in the Kinsey study counted kissing another person as infidelity (Lehmiller, 2025). A YouGov poll published December 20, 2018, sample size not given on the page, found 14% of Britons saying that passionately kissing someone other than your partner is not cheating, and 25% if there is mistletoe (YouGov, 2018).

On Mumsnet, a British parenting forum, a thread started June 26, 2026 (about 46 replies) came from someone who had kissed another person while drunk at a party and told the boyfriend only part of it. Replies were blunt: “So you cheated. Tell him and hope he leaves you.” and “You need to tell him. It’s not small and stupid is it?” (Mumsnet, June 2026). Like most Mumsnet threads we read, it is about a settled couple.

On The Student Room, a UK student forum, a thread started March 8, 2012 (about 16 replies), fourteen years old now, got a short answer: “yes it is cheating. That’s the answer.” The person who asked had set a condition in a reply: “Assuming one is in a relationship.” (The Student Room, 2012). Before that point, see not official yet.

Is watching porn cheating? Porn, OnlyFans and strip clubs

Most people surveyed say no. In the 2017 Deseret News survey, 19% called “watching pornography without your partner” always cheating, 28% sometimes and 53% never (Deseret News, 2017). In the 2014 YouGov US poll, 26% counted watching porn “while you’re in a relationship” (YouGov, 2014). In the Kinsey study it was one-fifth (Lehmiller, 2025), and on the iFidelity chart about 30%; the report’s text says a majority did not call pornography unfaithful (National Marriage Project, 2019).

Strip clubs split more: 23% always, 33% sometimes and 43% never for “going to a strip club without your partner” (Deseret News, 2017). Paying one person draws the most. In the UK survey, 47% called it cheating to “directly engage with sexual content creators”, the OnlyFans kind, with 33% choosing the middle and 6% harmless (YouGov, 2026b). In the Kinsey study, “nearly half (45 percent)” said so of a partner sending money or gifts to “a cam model” (Lehmiller, 2025).

The Mumsnet threads split along the same line. In one titled “Is OnlyFans a harmless outlet or am I right to be mad?”, started November 13, 2024 (about 88 replies), “OnlyFans is a lot more personal than porn and most people would regard it as cheating with a sex worker.” met “To me it’s no worse than porn so it depends what your boundaries on that are.” (Mumsnet, November 2024). A webcam thread started June 26, 2023 (about 26 replies) summed itself up: “Some think it is, some think it’s not.” (Mumsnet, June 2023). A strip-club thread started December 23, 2018 ran to about 437 replies, from “I don’t consider it cheating either.” to “How is it not cheating? I agree completely OP.” (Mumsnet, December 2018).

When we checked the search results for the porn question on October 6, 2026, two of the top pages came from a company that sells porn-blocking software and an advocacy group, and both said yes. Every survey we opened puts porn near the bottom, and we take no side on porn itself. Our reading: in these surveys the line sits between watching and paying or messaging one person.

Is sexting or texting cheating?

Explicit messages are close to settled. In the 2022 YouGov US poll, 90% counted sending nude photos of yourself to someone else, 83% suggestive online messages and 80% lying about spending time with another person (YouGov, 2022). In the Kinsey study, 72% of US singles called sexting infidelity (DatingAdvice.com, 2025). Ordinary texting splits. In a Mumsnet thread titled “Is texting cheating?”, started October 11, 2025 (about 41 replies), one reply said “Not cheating. I’m still friends with a couple of exes.” and another “The fact he was hiding it would be the major red flag to me” (Mumsnet, October 2025). Flirting and texting an ex are covered under is texting, flirting or sexting cheating.

Is it cheating if you’re not official yet?

Is it cheating if you’re just talking? Usually not, because there is no agreement yet to break. Every survey above whose wording we read writes a relationship into its question, and a talking stage has none until someone asks for one.

On The Student Room, a thread started June 6, 2022 (6 replies) asked whether kissing someone else in the speaking stage was cheating. One reply: “Unless you’ve had a chat saying you won’t get with anyone there I don’t see anything wrong with it.” Another questioned the label: “Right, so it’s not just ‘talking’, you’re seeing someone.” (The Student Room, 2022). A Mumsnet thread started January 28, 2025 (about 18 replies) was about a kiss at 19, before the relationship had a name. The poster wrote: “My partner doesn’t think it was cheating since we never properly spoke in person about what we were” (Mumsnet, January 2025).

Once you are dating, the default tightens. In a Student Room thread started March 1, 2021 (about 13 replies), from someone whose boyfriend’s best friend had seen them on Tinder, one reply said: “It’s not OK to be on a dating app while you’re dating someone, even if you don’t talk to anyone or cheat on them” (The Student Room, 2021).

Our view: if you would mind them doing it, that is a reason to have a DTR talk. The numbers people quote for when that talk happens are on how many dates before a relationship; a situationship is what it looks like when nobody does.

Can you cheat in an open relationship?

Yes, by breaking the terms the two of you set. A 2015 review by Rubel and Bogaert defines consensually nonmonogamous relationships as “those in which all partners explicitly agree that each partner may have romantic or sexual relationships with others” (Rubel & Bogaert, 2015). The deal is different, and it can still be broken.

Every survey in the table whose wording we read writes monogamy, a spouse or a partner into its question, so the table shows the monogamous default. Many people have lived outside it. In two Census-based quota samples of single US adults, 3,905 and 4,813 people, 21.9% and 21.2% had engaged in consensual nonmonogamy at some point (Haupert et al., 2017). In the 2022 YouGov US poll, 23% had ever been in “a non-monogamous or open relationship”, and 66% would only consider a monogamous one (YouGov, 2022).

Quinn and Stoll asked 176 people aged 18 to 62 in consensually non-monogamous relationships, by online questionnaire, whether sexting outside their agreed terms was infidelity: 51% said yes and 49% no. One participant: “if you have to hide it, it’s cheating” (Quinn & Stoll, 2022). The sample is small and self-selected. A Mumsnet thread titled “Open relationship?”, started July 9, 2023 (about 26 replies), made the same point: “Boundaries and rules can often be crossed so ‘cheating’ and betrayal can still occur if the relationship is open.” (Mumsnet, July 2023).

Casual dating, FWB and roster dating are usually not exclusive by design, so what counts there is whatever was said. An open relationship and the wider ENM umbrella have their own pages.

Is cheating illegal?

Not legal advice. Checked October 6, 2026.

No relationship law we found uses the word; the nearest term is adultery, and mostly in divorce. In England and Wales, the Divorce, Dissolution and Separation Act 2020 came into force on April 6, 2022, and the sole ground is now that “the marriage has broken down irretrievably”, so adultery no longer has to be proved (Divorce, Dissolution and Separation Act 2020, s.1). In New York, bill S8744, repealing the adultery law in Penal Law § 255.17, which dated from 1907, was signed on November 22, 2024 and took effect immediately (New York State Senate, S8744).

How to agree on what counts

How do I know if I’m cheating? Our rule of thumb: ask whether the two of you agreed you would not do this, and whether you would show them. A yes to the first means you broke the deal; a no to the second puts you at least in the middle of the table.

One figure suggests why it helps to agree early. In the 2022 YouGov US poll, 43% of those who had been in a monogamous relationship said a partner had accused them of cheating when they were not (YouGov, 2022). The poll does not say why. Our reading: a line only one partner knew about is one way to get an accusation like that.

One way to have the talk: each of you marks every row of the table with one of three answers adapted from the UK survey, “cheating”, “fine” or “not cheating, but not fine”, and then you compare. Three of ours, not tested at scale:

• “Kissing is out for me. Porn I don’t care about. OnlyFans I’d want to know.”
• “I’ve stopped seeing other people, and I’d like to know where you are on that.”
• “If one of us does something we marked ‘not cheating, but not fine’, we say so before the other finds out.”

If something has already happened, the steps on micro-cheating include saying what you saw and what you thought the deal was, and they rule out going through the phone. If checking turns into control or fear, the US and UK helplines are in the last step on our red flags page.

How to use this

• Read across a row. One act, several surveys; the spread is the answer.
• Settle exclusivity first. Before it, most of the table breaks nothing.
• Mark the table separately, then compare. The rows where you differ are the ones to talk about.
• Two questions when unsure: did we agree, and would I show them.