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Relationships

Mumsnet has not checked the qualifications of anyone posting here. If you need help urgently or expert advice, please see our domestic violence webguide and/or relationships webguide. Many Mumsnetters experiencing domestic abuse have found this thread helpful: Listen up, everybody

Do you believe "once a cheater, always a cheater"

176 replies

worldshottestmom · 25/03/2026 20:07

I just want to preface this before anyone jumps on me:

  1. I’ve never cheated and never would.
  2. I think it’s awful and I’m not trying to defend it at all.

Just interested in a general discussion really.

So, long story short one of my friends has been seeing a man for a couple of months and it’s starting to get a bit more serious. She thinks he’s great and can see it going somewhere, but her one hesitation is that he told her he cheated on his ex when he was 22. He’s now 31 (she’s 29).

it got us talking about the whole “once a cheater, always a cheater” thing. I’m a bit on the fence with it. I do think for some people it’s just who they are; no real morals, low self-esteem, impulsive, etc, and they’ll always cheat regardless.

But I also think there are cases where people cheat for different reasons (not excuses, obviously) — being unhappy in a relationship, insecure, drunk/stupid, drugs, etc etc. And especially when people are younger, I do think some are capable of growing up, having a period of self-reflection and growth, and gaining the morals and self-worth not to do it again.

I remember my mum always saying “a leopard never changes its spots” and “once a cheater, always a cheater” when I was growing up. And I do think that’s true sometimes. But is it naive to think people can actually change? That said, personally I don’t think I could be with someone if they told me they’d cheated in the past. It would just always be there in the back of my mind and wouldn’t feel worth the risk of not knowing and the uncertainty. I just wouldn't be able to trust them, personally.

On the flip side, I used to work with a woman who had an affair with a married man (she was also married at the time). They’re now married to each other and have been for years, seemingly happily. She said her ex was abusive and unsupportive, and his marriage had basically died. (Shes a massive over-sharer and told everyone everything, hence why I know all this!) It does make me wonder how that works though. wouldn’t you always have that doubt in the back of your mind? Especially given how their relationship started.

Although I suppose you never really know what goes on anyway, whether someone has cheated or not. If they haven't told you, id just be worried that i had simply not found out yet. Also, everyone who cheats has to do it for the first time at some point, so even someone with no “history” could still do it.

So… what do you think? Can an unfaithful leopard actually change its spots? or is it always the case that once a cheater, always a cheater?

And would you get into a relationship with someone who admitted they’d cheated in the past?

Also interested to hear from anyone who has pursued a relationship with someone that had cheated previously; did it work out or not?

OP posts:
TheFormidableMrsC · 26/03/2026 08:00

My ex husband was a prolific cheat. I didn’t find out much of the extent of it until he left and I probably will never know the whole truth. I don’t need to know now, I have made peace with the betrayal. However, the OW he left for was deeply insecure and tracked him everywhere. He won’t stop, it’s part of his very being I believe. He is definitely a case of once a cheat etc….

I certainly don’t think this applies to everybody though. I have a family member who did it and it was complicated and abuse involved. They never did it again.

Additup · 26/03/2026 08:01

I would say yes and no. Some people cheat as their modus operandi all the way through a relationship and thtoughout thrir life. In their case I would say probably yes, they are likely to cheat.

On the other hand, I cheated on ex boyfriends when younger (although we were technically on a break 😉) and my dh had a girlfriend when we met (although the relationship had run it's course) so we are both technically cheats. This all happened in the heady days of the 1990s.

We've been married coming up to 25 years and no cheating on either side so for people like me I would say no.

flipperdipper5 · 26/03/2026 08:07

No I don’t. I also don’t think cheating makes you a fundamentally bad person. Of course if you’re just doing it for a laugh and bit of fun on the side then yes it’s very wrong. But it’s not always that scenario.

I cheated years ago. I’d been in a dead end relationship with a cock lodger for a long time. Tried to speak to him several times but nothing ever changed. It became soulless and then someone at work showed a bit of interest, I’m only human and the rest is history. I’m glad I did it as it was the push I needed to get out of that relationship for good but there’s no way I’d do it to my dh because a) this is a totally different relationship and b) people change.

If we are talking about someone who is wilfully deceiving their partner and trying to have their cake and eat it then that’s different. My relationship was already dead and yes I could have done things better/differently but none of us are infallible.

There are many grey areas in life.

EllaPaella · 26/03/2026 08:14

I think some people are very good at just doing what they want then re-writing the narrative in their head to convince themselves they’ve done nothing wrong.
Ultimately I see cheats and liars as very weak people with low emotional intelligence and a low moral compass so whether they would cheat again would be irrelevant to me.

BoudiccaRuled · 26/03/2026 08:27

OneShyQuail · 25/03/2026 20:14

Yes.
Very simple

There is no "reason" to cheat. At least have the decency and balls to leave properly. I wouldn't be interested in someone with no morals and empathy

I used to agree with this but know two men who married at haste, cheated a great deal then ran off with their mistresses whom they were then married to, seemingly very happily, for decades until death divided them.
Being weak, a coward, and not being able to pluck up the courage to leave in a civilised manner does not always equate to "once a cheat, always a cheat" in my small experience.
But I still wouldn't go there!

Epidote · 26/03/2026 08:28

People change and someone who cheated in the past may have changed enough to not do it in the future, because they have acquired the maturity of knowing that cheating is not the answer to whatever makes you unhappy.
Serial cheaters are always looking for the thrill and the upgrade, those are the ones that will never change because they are stuck in a phase of life that people should leave behind in their twenties and never is their fault or responsibility. Selfish people will always look someone to blame and look for that upgrade they won't change.
An idiot who cheated once when younger may well not do it ever again either because now is mature enough to see the real stuff, they don't have the opportunity to have a big upgrade or they can be bother but who knows which is the reason.

Sunshinemoonlightboogie · 26/03/2026 08:34

I cheated when I was younger (late teens/very early twenties) a few times. I have never cheated since then, I wouldn’t, I understand the damage and see it as abusive behaviour. I changed, I grew, I matured.

I have been cheated on in every subsequent relationship, including my marriage. Do I think my husband will cheat again, no, I hope not, I guess I think if I can change he can too. If I can see the damage and be a better human, so can he.

I move through life trusting myself more. I trust myself not to cheat, I trust myself to leave if my husband cheats again, but I do think people can change.

But I think change is hard, once you get older and I think stats show that if you’ve cheated, you’re 3-4 times more likely to do it again in a subsequent relationship. So it’s wise to see previous cheating as a red flag and look at context closely.

User38512054 · 26/03/2026 08:42

Scottishskifun · 26/03/2026 07:54

Honestly I think there are 2 different types.

There are the ones who cheated when young early 20's etc because they are young and foolish. But also often would be in a relationship when they should have broken up way before the event.

Then there are those who think it's acceptable regardless at any stage in life.

The first definitely can and does change the second no they don't.

I know many of the first camp and all now in marriages for 8+ years have never cheated on their spouses.

I know 1 of the second now onto their 3rd affair partner.

So, what about somebody that first cheats in mid life, do they then automatically become serial cheaters from then on?

My experience says not.

AgeingBanana · 26/03/2026 08:44

I don’t think they’ll always cheat again. But personally I wouldn’t take the risk and date someone if the cheating was prolonged (rather than a one-off) and/or relatively recently.

There are some factors that make it more likely that they’ll always be a cheat. If they had a full-on extended affair in a very committed relationship, I think they’re likely to do it again. It shows a huge flaw in their character. A one off episode or cheating as part of leaving a bad relationship while young and immature, I’d say they could have learned from it and not be likely to reoffend. It’s still not acceptable, but people do make mistakes early in their dating lives.

Needhelp101 · 26/03/2026 08:46

I was a cheat at 19 because I was a bit of a twat.
I was married for years and never thought about cheating. Ironically, my then husband turned out to be a serial cheat, including a two year affair with someone i thought was a close friend. Karma, eh?

MysticTree · 26/03/2026 08:49

Interesting.

In general, humans repeat certain patterns of behaviour because thats how our brains work.

Therefore, if someone has resorted to cheating before in moments when they felt dissatisfied or needed attention etc then yes, I believe they will absolutely do it again when they feel that same emotion again. The best predictor of future behaviour is past behaviour. If it wasn't, then noone would have a personality because your personality is simply a set of thoughts/behaviours that make you, "you".

That said, people can change if they are motivated to do so but it takes work to change and unless someone has actively done that work to change then they will likely default to previous behaviours to manage uncomfortable emotions.

EnterQueene · 26/03/2026 08:55

I think the potential to cheat is there, but it is not inevitable they will cheat again, it depends on the circumstances.

My mum cheated on my dad then left him for the other man (who was also cheating on his wife). They both, so far as I know, have stayed faithful to each other through a pretty long marriage. However, it would not be wildly out of character for one or other of them to have cheated as they are both pretty selfish and transactional in their approach to relationships. As it happens, they found each other and meet each others needs well.

My mum has a streak in her that is quite selfish and good at compartmentalising people's feelings. I love her, but I know her well. She has only cheated with one person as far as I know but she has the potential for duplicity to her loved ones when it suits her.

User38512054 · 26/03/2026 08:57

In general, humans repeat certain patterns of behaviour because thats how our brains work

Our brains also learn not to repeat past mistakes from the consequences of those mistakes. Be it touching a hot stove when told not to or the emotional trauma resulting from infidelity.

MammyofaSuperBaby1993 · 26/03/2026 08:57

My ex cheated before me, then did the same to me when we married and will probably do the same to his current girlfriend. I have no doubts about it because he blames everyone else for it happening and has taken zero responsibility for destroying those relationships so he hasn't learned anything.

User38512054 · 26/03/2026 08:58

I think the potential to cheat is there, but it is not inevitable they will cheat again, it depends on the circumstances

As it is with everybody.

SerenitySeeker4 · 26/03/2026 08:58

Yes. Always.

FrauPaige · 26/03/2026 08:58

In your specific example, the actions of a 22 year old are irrelevant for their behaviour at 30, 40 or 50. Some people may have tried tobacco, pot, and recreational pills at university but would never do so in later life, just as they may have had green hair at university but wouldn't do so in fully fledged adult life.

Conversely, there are plenty of circumstances where people who have never cheated do. There has to be a first time for every cheater - no one is born a cheater. That first time could be at 25 when they are early career and on the dating circuit or 45 when they have achieved seniority and have the means and cloak of mentorship, for example.

Clearly if somebody has a history of repeatedly cheating, that is a clear indicator that they are shit and that you should steer clear.

OrlandointheWilderness · 26/03/2026 08:59

yes.
if someone could justify it to themselves once then they could again.

EnterQueene · 26/03/2026 09:01

User38512054 · 26/03/2026 08:58

I think the potential to cheat is there, but it is not inevitable they will cheat again, it depends on the circumstances

As it is with everybody.

I don't agree. Some people are more likely to lie to people they love, they have the ability to put themselves first, rationalise and justify their behaviour and compartmentalise any hurt they cause. Not everyone will cheat, someone who has done so once is a red flag. It is not inevitable they will repeat the pattern but there is something in their character that makes it more likely if the circumstances emerge.

BillieWiper · 26/03/2026 09:08

I don't know. It's certainly more likely to happen repeatedly than it is to happen once to someone who'd never thought of it before.

I know I have cheated on boyfriends I didn't consider serious and didn't love. When I was a teen/20s. Now I feel like I never would. So it depends on your circumstances and maturity and understanding of relationships.

Even consent. As in I feel I dated people I didn't want to just because I did something sexual with them. Or not have the confidence to turn men away sexually. When I was very young.

wendywoopywoo222 · 26/03/2026 09:11

I cheated on my husband. He was a vile abusive narcissistic cruel man who had me believing after 20 years that I was an unattractive disgusting human being and when a man showed interest at work I went ahead with an affair. It was short lived and I have no regrets as it gave me the confidence to walk away from a very unhappy life.

Now in a very happy relationship with a lovely kind patient man, I didn’t know relationships could be like this and I would never cheat on him.

I don’t care if people think badly of me as I know it changed my life for the better, I still see the affair partner in passing sometimes but feel nothing but friendship towards him.

so yes I do think people can change although having arranged accommodation for conferences and working away for a lot of years also know that some people just are prolific cheaters as they have the opportunity.

Belladog1 · 26/03/2026 09:24

No.

I cheated on my husband. We had been married for 30yrs and we hadn't been initiate for about 5yrs and he was more interested in a bottle of vodka than me. I felt so bloody alone.

I ended up, after one god awful evening, signing up with Ashley Maddison (gosh, even writing those words sounds seedy). I didn't want to leave my husband, and I just wanted to be touched again. Anyway, it was a horrible website, but I ended up meeting just one man who was in the same situation as me and I was the only woman he met with. We literally signed up on the same day. I am still with him today and I left my husband last year.

I would never do it again.

AliasGrape · 26/03/2026 09:25

My ex and I got together very young and daft, lots of teenage/very early 20s drama, plus both being away for uni/ work so LTR and we both had moments of doing stuff we shouldn’t.

We had a proper ‘right what are doing because this can’t carry on, do we split up or grow up?’ moment and decided to stay together, moved in together, eventually got engaged etc and it was my understanding that we were going to be entirely faithful from that point, build our future together. Which is what I was doing, but no surprises that he had a different understanding and had continued cheating all along.

Never cheated, or even considered it, with anyone since and I’ve been with DH over 10 years now.

I think if someone cheated in a marriage, or a committed, established and grown up relationship as a fully formed adult I’d be less inclined to believe they would be entirely faithful in future. But I don’t think what someone did at 22 is necessarily a permanent stain on their character either. If there’s no other causes for concern I might proceed but maybe with a little extra caution!

Beetlebum89 · 26/03/2026 09:29

Generally, yes, I believe a leopard doesn't change its spots. It's complicated sometimes, cheating isn't always black and white. Lots of factors can lead a person to cheat. I know of someone who cheated once, but never again. It's a rarity, imo, but I suppose people can change. Are people who have been to prison always criminals, because they once were??? I don't condone cheating but sometimes I understand why people do it.

MysticTree · 26/03/2026 09:31

User38512054 · 26/03/2026 08:57

In general, humans repeat certain patterns of behaviour because thats how our brains work

Our brains also learn not to repeat past mistakes from the consequences of those mistakes. Be it touching a hot stove when told not to or the emotional trauma resulting from infidelity.

Fading affect bias. Its a powerful psychological phenomenon.

This is why it happens. You see it with addicts all the time.