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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

AIBU to think the "100% sure he’s never cheated" crowd are naive and delusional?

624 replies

IceCream233 · 18/07/2026 06:16

I’m looking for a bit of a reality check on relationship statistics.

I often see threads on here where 80% to 90% of posters insist they are absolutely, 100% certain their husband has never cheated.

Trust is great, obviously, but looking at actual statistics, it's just mathematically impossible for everyone to be right.

General studies on infidelity show that around 50% of married men will stray at some point. Plus, we all know that a massive chunk of people who cheat are just careful enough that they never get caught.

The math completely falls apart here. It means a huge portion of women who feel totally secure right now are actually being lied to, they just don't know it yet.

Are people just telling themselves "not my husband" as a coping mechanism to keep themselves happy? Is a bit of delusion just a basic requirement to survive a 20-year marriage?

AIBU for looking at the cold numbers instead of just relying on a gut feeling?

OP posts:
sunnydayyzz · 18/07/2026 11:24

My exhusband wasn't 'the type' either, quiet, shy, hard working, geeky. Turned out not only was he trying to shag pretty much every woman at work, he also had his eye on a few of the men as well.

I had 100% trust in him for going on 20 years and I was deluded! never thought for a minute he would cheat - or that he was bi for that matter.

Overtheatlantic · 18/07/2026 11:25

Why have you started this thread? Because you don’t want to be all alone with a cheating husband? What difference does it make what other men do?

Plumnora · 18/07/2026 11:30

You are definitely NOT delusional. At the age of 54 I've come to realise that sadly, if they thought no they can get away with it, most men will cheat. Not all, but a lot more than most women seem to realise.
And for this reason I decided to stay single.
Men tell us what we want to hear, and women believe what we want to believe.
Humans are not 100% monogamous by nature and with so many "dating" sites available now, more men than ever are being fed the belief that they can stray with no strings and nobody will know.

TheNinkyNonkyIsATardis · 18/07/2026 11:30

Thepeopleversuswork · 18/07/2026 11:16

@TheNinkyNonkyIsATardis

Exactly right. But this underlines what a nonsense it is to claim to have certainty about the inner life or future behaviour of another person.

The whole concept of certainty relies on proof. By definition you cannot prove to know behaviour which is in the future. Even the people who have actually been cheated on cannot know it will happen again.

You can have a very strong conviction about the likelihood of infidelity in your relationship and your conviction may be correct. But you can’t know. Of course you can’t.

Yes, you've just reminded me that there's also categories of "correctly know that they haven't been cheated on, but will/won't be in the future".

Because the actual statistic can only be determined once all the marriages included are over, by whatever means.

Someone was banging on about the fertility rates of 30yo, and saying that we'd have no future, because their present fertility rate is low. But you can only determine that once the race is finished! Of my antenatal group, only 10% were under 30, but by the max age of 40, 100% of us had children (obviously a self selecting sample).

scoopsahoooy · 18/07/2026 11:32

You definitely can't know anything for certain.

For me it's not that I think my husband is incapable of cheating ever (although I'd hope it's as unlikely as it seems - but I think pretty much everyone is capable of it, given the 'right' circumstances), but I would bet my house that he hasn't thus far in the last 14 years. There's quite a few reasons why I think that - opportunity due to how our life is set up, health issues over big chunks of that time, the amount of time we spend living and working together, who he is as a person, our relationship generally - so I don't think I'm being naive. Maybe one day those things will be different, but I'm not worried now and if I ever thought it seemed more likely, then I'd reconsider our relationship.

heathspeedwell · 18/07/2026 11:33

Having worked in a media environment where we had lots of overnight trips away, I am sad to say that around 80 - 90% of the married men I worked with made a drunken pass at me at some point. This is even though they knew I was very happily married and I had never given them any indication whatsoever that I was interested in them. I think a lot of men just try their luck in that hope that occasionally they will get lucky.
Sadly a similar number of them would freely admit to going to strip clubs and having lap dances if they were on a stag do, but not many of them would admit to paying for a 'happy ending'.
There are some lovely, honest, dependable men out there but I genuinely think a lot of men are more dodgy than we realise.
I'll never forget that around a third of men in the US paid Pornhub to watch the real footage of a 14 year old girl being gang raped. It was the most-searched thing on there for a long time. Lots of those men were husbands and fathers. I bet their wives thought they were good men.

ThatCyanCat · 18/07/2026 11:34

There's a lot of talk about "not the type" to cheat.

So what is the type? Should be very easy for women to swerve them if it's that easy to tell who is and isn't the type to cheat.

MandemChickenShop · 18/07/2026 11:37

many men will cheat if they have the opportunity. but most don't have the opportunity.

the number of men that actively look for extra is much lower, as men are often fairly lazy

Thundertoast · 18/07/2026 11:38

Im going to be honest, and this is just my experience, but the only people I know in real life who would say that are people who got together with their partner very early in life and are naturally, understandably, quite naive and sheltered from the complexities of relationships. The kind of people where a breakup would land like the world was ending because it just doesnt occur to them that it might happen, they've never thought about it, its never occurred to them that most relationships end in breakups, they have no understanding of a breakup as it is: a normal part of life, that sucks, but you do survive, so have zero emotional preparedness for it.

TheNinkyNonkyIsATardis · 18/07/2026 11:38

heathspeedwell · 18/07/2026 11:33

Having worked in a media environment where we had lots of overnight trips away, I am sad to say that around 80 - 90% of the married men I worked with made a drunken pass at me at some point. This is even though they knew I was very happily married and I had never given them any indication whatsoever that I was interested in them. I think a lot of men just try their luck in that hope that occasionally they will get lucky.
Sadly a similar number of them would freely admit to going to strip clubs and having lap dances if they were on a stag do, but not many of them would admit to paying for a 'happy ending'.
There are some lovely, honest, dependable men out there but I genuinely think a lot of men are more dodgy than we realise.
I'll never forget that around a third of men in the US paid Pornhub to watch the real footage of a 14 year old girl being gang raped. It was the most-searched thing on there for a long time. Lots of those men were husbands and fathers. I bet their wives thought they were good men.

I have a friend from childhood who ended up in a friend group at uni that had a "cheating culture". Both her female best friends cheated frequently, and they had the opportunities, with long distance boyfriends and girlfriends egging them on that it was ok.

She cheated on her last partner with her new partner, then cheated on him for at least a year into their relationship. She was very embarrassed when her pro-cheating friends revealed this to the rest of us at her hen do - we were all appalled. (In fact, I had to take one of the husbands home from a party once because said friend was cheating on her now husband then, and I had to take him away to calm down).

Does that mean that all us "shocked and appalled" lot are immune from cheating? Or the appalled husband? No, sadly not.

But I do think the "everyone does it" brigade are often in a situation where there's a high opportunity and culture of excusing it. It can't help.

SwirlingAroundSleep · 18/07/2026 11:39

ExBert80 · 18/07/2026 07:35

The older I get the more I think the concept of marriage and faithfulness is ridiculous. Why must love between two people be exclusive? Who said? Hasn’t life moved on? I am married, I don’t know nor care whether my partner has cheated. I have no interest in cheating myself, just no interest in men at this point. Maybe it’s an age thing but the amount of time and angst wasted on relationships- is he cheating, has she strayed, is he thinking about someone - it just seems childish looking back on life. The women who want to police their partners thoughts is alarming - is he thinking about other women, does he find other women attractive - yes, he is and does. So do women. It’s unrealistic to not find others attractive. Marriage is a straitjacket for all, foisted on us centuries ago, but our more sophisticated way of life still clings onto the outdated concept of monogamy.

We are on Earth a short time but we have all been sold a pup when it comes to relationships. Women get shackled up with unsuitable men, thinking they can change them, because society has told them you have to be in a relationship- using up precious time on deadbeats, making being in a relationship the be all and end all of life. It isn’t.

In answer to the OPs question, I do think people are delusional about the thought of their partner cheating. But then I think most people are delusional about monogamous relationships in general. (edited for typo)

Edited

But it’s not biologically speaking ridiculous to want a partner dedicated to you and your children who is not going to accidentally procreate with some else. There is immense advantage in being a team raising your children together and monogamy ensures that it will only be your children you raise. In addition time outside of work is sparse and previous and I wouldn’t want my DH to be spending that with another woman. I’m not jealous, if he did I’d tell him to sod off and do as he was pleased but I have far higher standards for myself than to let him back into my bed. The truth is I can survive on my own, I’m financially and emotionally stable but I have a partner so we’re a team. If he’s cheating then we’re no longer a team and I’m done. I would expect the same response from him if I cheated and my respect for him (and our relationship) is why I never would. I genuinely don’t believe he would either as he was married before and ended the relationship when they were both unhappy, for me realising you don’t want to be together and ending things is the better option rather than betrayal. We don’t have to be so old fashioned people are married for life no matter what, but in a world where you can divorce there is absolutely no excuse for cheating.

EmeraldShamrock000 · 18/07/2026 11:42

I know my DH hasn’t cheated and nor have I.
There is no guarantee that either of us won’t meet a new person and fall madly in love but neither will cheat for the sake of a quick fumble.
We don’t have exciting lifestyles to offer the opportunity. We’re both home after work.

geekone · 18/07/2026 11:49

Your figures are just wrong. In the U.K. around 20-25% married men cheat and 15-20% of women, it’s not as common as Mumsnet makes it out to be. Also even if it was 50% it doesn’t mean that the women saying my DH would never cheat are mistaken, you could talk to 200 men and it is possible none of them have cheated in the same way as all of them
could have. Other women’s views on their partners shouldn’t really be your concern.

MixedBouquets · 18/07/2026 11:51

Thundertoast · 18/07/2026 11:38

Im going to be honest, and this is just my experience, but the only people I know in real life who would say that are people who got together with their partner very early in life and are naturally, understandably, quite naive and sheltered from the complexities of relationships. The kind of people where a breakup would land like the world was ending because it just doesnt occur to them that it might happen, they've never thought about it, its never occurred to them that most relationships end in breakups, they have no understanding of a breakup as it is: a normal part of life, that sucks, but you do survive, so have zero emotional preparedness for it.

I’ve been with DH since our student days and am nowhere near that blinkered, so it’s not baked in to early coupling off. I absolutely can’t claim DH hasn’t slept with someone else — for ten years I spent half the year working in another country, and we both travel for work so we both have had ample opportunity. I also don’t particularly mind if he has. I don’t think it’s the worst thing you can do in a relationship.

And obviously we’ve experienced it in our various circles of friends and family, though I think the only two that absolutely blind-sided both of us were (1) a particularly united and cool couple who ran a multi-award-winning business together, when he fell head over heels for someone he literally bumped into in a doorway while working abroad, having previously been genuinely happy and (2) when our childminder left her husband for the dad of one of her mindees, who was also our DS’s teacher.

But these things happen. You can never predict people’s effects on people. I’ve certainly had my opportunities, despite also being happy with DH. It’s normal. There’s no one, single soulmate for each of us, and most of us will at some point run into one of our others, with whom we could have been differently happy if we’d met when single. With one of mine, a colleague, it was absolutely mutual. We just never discussed it or acted on it, and it subsided over time.

Remaker · 18/07/2026 11:58

But how do we know about this large group of people who cheat so carefully they never get caught?

I had an argument with a good (married) friend before my wedding. We opted for traditional vows albeit not in a church. She said I was naive to promise til death do us part ‘because 50% of marriages end in divorce’. I said if I was assuming that there was a strong chance of us divorcing then I wouldn’t be getting married. We have made it to 22 years so far.

What is achieved by believing your partner might cheat on you? Does it stop the hurt to think oh I thought that might happen? Are we really so worried about looking foolish that we will spend our lives anticipating infidelity?

Beer3000 · 18/07/2026 11:59

Why would you ever marry someone, unless you though they were a good, loyal person with decent values?

That is why affairs are devestating, rather than an accepted part of life.

But, IMO, better to be wrong about someone, than to have realistic but low standards.

DaysIllRememberAllMyLife · 18/07/2026 12:04

You said math so I'm assuming you're American . They aren't British stats for infidelity. Are they American?

TheNinkyNonkyIsATardis · 18/07/2026 12:06

EmeraldShamrock000 · 18/07/2026 11:42

I know my DH hasn’t cheated and nor have I.
There is no guarantee that either of us won’t meet a new person and fall madly in love but neither will cheat for the sake of a quick fumble.
We don’t have exciting lifestyles to offer the opportunity. We’re both home after work.

To be clear, I haven't and don't intend to cheat.

But I think there's more of an argument for a random episode of lust when separated being less harmful than a prolonged affair including sustained lies.

Thepeopleversuswork · 18/07/2026 12:06

Beer3000 · 18/07/2026 11:59

Why would you ever marry someone, unless you though they were a good, loyal person with decent values?

That is why affairs are devestating, rather than an accepted part of life.

But, IMO, better to be wrong about someone, than to have realistic but low standards.

Well obviously no one goes into a marriage thinking they are marrying a cheat. But there’s often a gap between the promise and the reality. Thats where the unpredictability comes from.

Thinking someone has strong morals is a decent signal. Its not an insurance policy.

Catwalking · 18/07/2026 12:09

“AIBU to think the "100% sure he’s never cheated" crowd are naive and delusional?
0 replies
IceCream233 · Today 06:16
I’m looking for a bit of a reality check on relationship statistics”

Why?

Highlighta · 18/07/2026 12:10

Beer3000 · 18/07/2026 11:59

Why would you ever marry someone, unless you though they were a good, loyal person with decent values?

That is why affairs are devestating, rather than an accepted part of life.

But, IMO, better to be wrong about someone, than to have realistic but low standards.

Many women marry for security reasons.

Or it's an arranged marriage.

Or religious reasons.

There are lots of reasons, and some don't include love and loyalty.

EmeraldShamrock000 · 18/07/2026 12:13

TheNinkyNonkyIsATardis · 18/07/2026 12:06

To be clear, I haven't and don't intend to cheat.

But I think there's more of an argument for a random episode of lust when separated being less harmful than a prolonged affair including sustained lies.

I get that.
I am not naive, my ex was an emotionally unstable serial cheat.
DH is different, for some reason he really loves me, he is very kind sweet man who can’t cope with conflict and he is unmotivated too.

I love him with all my heart. He loves me much more. That’s not being pig headed, I don’t understand it either, I know he wouldn’t risk losing us, he knows I wouldn’t give him a second chance.

namechange6766333545544 · 18/07/2026 12:32

I’m confident that my husband hasn’t cheated and wouldn’t cheat, but I’m not 100% because i don’t think any of us can be certain about anything.

Additup · 18/07/2026 12:38

Plumnora · 18/07/2026 11:30

You are definitely NOT delusional. At the age of 54 I've come to realise that sadly, if they thought no they can get away with it, most men will cheat. Not all, but a lot more than most women seem to realise.
And for this reason I decided to stay single.
Men tell us what we want to hear, and women believe what we want to believe.
Humans are not 100% monogamous by nature and with so many "dating" sites available now, more men than ever are being fed the belief that they can stray with no strings and nobody will know.

Tbf I really don't think this is just a male thing. If there was a 100% guarantee that you could have sex with a crush then I bet most women in relationships wouldn't pass either.

KnickerlessFatWoman · 18/07/2026 12:41

ClayPotaLot · 18/07/2026 07:06

YABU

While it's highly unlikely that they are all correct, mathematically it's perfectly possible

The responders are not a random sample. People who have doubts are far less likely to post. So there's plenty of space, mathematically, for the 80%-90% of posters who say there partners would never cheat to be from the part of the population whose partners have never cheated.

Exactly this. Your supposed maths completely ignores that your sample pool of women naturally skews towards those who are confident in their marriages, and may well have reason to be. There may well be plenty of MNers out there who aren’t so sure of their husbands’ faithfulness, but they’re not posting to announce that.