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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

Would you/should you tell someone their spouse had an affair?

137 replies

KeepOff · 06/03/2026 01:38

If you had absolute proof?
If it was many years ago?
What if you didn’t know them?
What if you know because the affair was with you but you didn’t know then and have only just found out?

Or is it best to leave it well alone?

OP posts:
KeepOff · 06/03/2026 07:41

HopSpringsEternal · 06/03/2026 07:32

I would want to know if my husband was pursuing someone he had an affair with. Im amazed so many people wouldn't.

Technically, she was the affair as I’d been with him several years by the time he started seeing her but I agree, the fact that he recently got in touch with me saying he was single makes the old cheating present material. I know they met online so he was actively looking to cheat, and with hindsight, probably not for the first time. I’m almost certain she didn’t know about me based on what she was posting at the time. I’d also want to know but seems we’re in the minority.

OP posts:
Adelle79360 · 07/03/2026 13:52

KeepOff · 06/03/2026 06:41

I am the ex. He started dating another woman before our relationship ended. I was the one who ended it but it was amicable, in part because I didn’t know he was cheating. He subsequently married the other woman. He recently got back in touch and told me he had left her because she was abusive. I checked SM to see if this was true and it turns out they are very much still married and I also discovered their relationship started months before he told me it did. My question is, does she have a right to know or should I leave it since so much time has passed. He also doesn’t know I know.

Why didn’t you just explain it this simply in the OP?!

Anyway, perhaps she knew he was with you when she started seeing him? Rarely does knowing they have a partner stop people from getting involved.

Personally given your updates I’d just block and delete. You don’t owe her anything, and I wouldn’t give him the satisfaction of even responding to ask him to stop contacting you.

Swiftie1878 · 07/03/2026 14:04

KeepOff · 06/03/2026 07:41

Technically, she was the affair as I’d been with him several years by the time he started seeing her but I agree, the fact that he recently got in touch with me saying he was single makes the old cheating present material. I know they met online so he was actively looking to cheat, and with hindsight, probably not for the first time. I’m almost certain she didn’t know about me based on what she was posting at the time. I’d also want to know but seems we’re in the minority.

Edited

I’m on Team Tell, too.

Pessismistic · 07/03/2026 18:29

Op do you know her personally or on social media? I might be tempted to message her and ask if they have really split up as your considering going back to him as he is now single then see what her reply is . Op then mention to her that she was the other woman back in the day when you were dating him. Let him talk himself out of that conversation.

BlueYazoo · 07/03/2026 18:48

I once told a friend about her partner’s affairs as she would spend hours analysing his every move, constantly obsessing that he was cheating and always asking if I had heard anything/knew anything. However, he lied, she chose to believe him, he turned it all around on me and I was left out in the cold. They got married and had children, he never changed his ways. Sadly she passed away not long ago but we never regained that friendship. Never again will I ever tell anyone the truth in this regard

Justaspy · 07/03/2026 18:48

Do it anonymously

Tuesdayschild50 · 07/03/2026 19:59

Absolutely no.. its the past who are you trying to hurt because that's all you'll be doing.
Get a life of your own and you won't care.

Awwlookatmybabyspider · 07/03/2026 20:04

No where affairs are concerned see nothing say nothing hear nothing especially if they had kids. Not only that but for all I was to know they could have an open relationship.

jrc1071 · 07/03/2026 20:14

Heatedrival · 06/03/2026 06:06

No. You don’t know if they would be physically harmed by their OH and I couldn’t risk that.
Also you never know all the circumstances and I’m not a sanctimonious twat.

I agree. SS wife is the primary relationship, he is a narcissist. He is using that to get supply. And if she tries to leave, he may become physically violent, just so he can maintain his image.

Zerosleep · 07/03/2026 20:19

Stay out of other peoples business and leave it alone. Things have a way of coming out and someone else’s relationship is nothing to do with you. The only way I would say something would be if it was a close family member or my best friend.

StephensLass1977 · 07/03/2026 20:23

No, I'd leave well alone. Been through this way too many times and have never once been thanked or shown any gratitude for telling a cheated-on spouse. Because most people's default is to try and hold onto what is familiar to them, the messenger always gets shot.

Lookingdownthebarrell · 07/03/2026 20:27

My Ex cheated on me. His friends knew at the time. For years i had a “good marriage” with some issues in important areas, I
felt that something was off but because he was “a good man” I spent my heart and soul
trying to fix myself.

I found out much later. I don’t care about people’s motivation for telling me. I would want to be told because I’d want to know and then decide what I wanted to do. The ex did not do the work to repair the things that were wrong with us so I left. Because I knew it wasn’t about me it freed me to leave - that is it. It frees people who like me think the problem is with us. Because the cheater has is fixing the problem in other ways we can’t actually fix anything.

TheHillIsMine · 07/03/2026 20:47

You clearly want to tell her and your posts are all so obvious.

KellyAnne47 · 07/03/2026 20:51

You're not Gordan Ramsays supposed ex mistress are you..... 🔪💰

OneBreezyHelper · 07/03/2026 20:53

KeepOff · 06/03/2026 06:15

Yes, that is the question - would you tell the innocent spouse if you had inadvertently been an affair partner? The guilty spouse will not tell them. In this case, it is not a gullible person but a situation where the end and beginning of two relationships overlapped and neither of them knew.

so it has nothing to do with "doing the right thing", you are just bitter and want revenge because you are allegedly "innocent" too?

It's mean. Fair enough to be jealous about the first or official partner, you are human, but it's cruel to try to ruin their life to make yourself feel better.

Nevermind17 · 07/03/2026 20:57

HopSpringsEternal · 06/03/2026 07:32

I would want to know if my husband was pursuing someone he had an affair with. Im amazed so many people wouldn't.

I agree. I’m guessing they’ve never lived through the hell of a cheating spouse - the mind games, the gaslighting, the feeling that you’re losing your mind and have no idea why, the unsettling suspicion that there’s someone else but with no evidence to pin it on you just convince yourself it’s all in your head.

I really wish someone had told me.

AcrossthePond55 · 07/03/2026 21:38

@KeepOff

So the 'overlap' was the end of your relationship with him and the beginning of hers. I agree with @BarbiesDreamHome , I'd leave that out. I would tell her he's been back in touch and has alleged that they are separated due to her (supposed) abuse.

Sorry if I missed it, but do you have any texts from him to send as proof? Because he's likely to deny it all, although I suppose that's not your problem.

If his wife does get in touch with you I'd only mention the 'overlap' if she says anything about the end of your relationship.

Missj25 · 07/03/2026 21:43

KeepOff · 06/03/2026 06:09

I’m so sorry. This was my very similar personal experience as well which may be colouring my view.

It’s different, her friends knew & didn’t tell her , you’re not friends with your Ex affair partners wife .
Why would you tell her now of something that happened so long ago ?
Why has he contacted you again ?

Moonshild · 07/03/2026 21:54

I was in this dilemma a few years ago and I’m glad that I chose to say nothing and let it play out.
It wasn’t my business.
I knew all parties involved and did tell the ‘ mistress’ that she should walk away - she didn’t and it was a very unpleasant situation for her and many people around them.

ForCalmScroller · 07/03/2026 22:01

Can't stand these types who want to cause carnage to multiple people's lives as its 'the right thing to do', get over yourself.
You could be opening yourself up to revenge attacks, wont feel so smug then will you?

Purplecatshopaholic · 07/03/2026 22:03

If it was happening currently then most likely yes. I was cheated on and I wish someone had told me. If it was old news then no, what good would it do.

KeepOff · 08/03/2026 00:19

Adelle79360 · 07/03/2026 13:52

Why didn’t you just explain it this simply in the OP?!

Anyway, perhaps she knew he was with you when she started seeing him? Rarely does knowing they have a partner stop people from getting involved.

Personally given your updates I’d just block and delete. You don’t owe her anything, and I wouldn’t give him the satisfaction of even responding to ask him to stop contacting you.

Because, I knew as soon as I provided any details at all, posters would start projecting and filling the blanks with made up stories such as: I’m obsessed with him, or I am trying to hurt her, or I’m jealous and I don’t have a life and I can’t possibly be motivated by altruism or thinking this might be the right thing to do. The neutral framing was an attempt to get posters to answer the question I am asking myself: should I tell his wife this information?

Based on what I’ve seen, I really don’t think she knew about the overlap, but if she did, she’s not going to be bothered by the information so it’s immaterial to the dilemma. He is already blocked.

P.s. I also know I’m going to be told repeatedly to block him even though he is blocked on everything he can be blocked on. He calls me from a withheld number and has emailed from a throwaway account before. No, I can’t ignore withheld numbers because my daughter has significant health needs and I get a lot of legit withheld medical calls. No, I won’t change my number - I’ve had it 25 years and it will be a massive hassle. Yes, I will tell him not to contact me again if he calls. This is not directed at you btw, just getting the answers in early.

OP posts:
MsSmartShoes · 08/03/2026 00:20

I would want to know if my marriage was a lie.

KeepOff · 08/03/2026 00:21

Pessismistic · 07/03/2026 18:29

Op do you know her personally or on social media? I might be tempted to message her and ask if they have really split up as your considering going back to him as he is now single then see what her reply is . Op then mention to her that she was the other woman back in the day when you were dating him. Let him talk himself out of that conversation.

I don’t know her. I’d never even looked her up before this week. We have no mutual friends either. That’s a clever way of framing it actually. If I decide to message her, I will do it like that. Only downside is that he might think I want him back 🤢

OP posts:
KeepOff · 08/03/2026 00:27

BlueYazoo · 07/03/2026 18:48

I once told a friend about her partner’s affairs as she would spend hours analysing his every move, constantly obsessing that he was cheating and always asking if I had heard anything/knew anything. However, he lied, she chose to believe him, he turned it all around on me and I was left out in the cold. They got married and had children, he never changed his ways. Sadly she passed away not long ago but we never regained that friendship. Never again will I ever tell anyone the truth in this regard

That’s really sad @BlueYazoo. I agree, there’s a really good chance she won’t believe me but I’ve been called by the OW before and left him (XH, not this guy). She gave me the missing information I needed to piece all the clues together and finally see through his gaslighting. She was actually really unkind in the way she told me but I was still grateful to know the truth. I don’t run the risk of losing a friend in this situation but I can imagine that would add another layer to the dilemma. Conversely, I would tell someone close to me without hesitation because keeping secrets for cheaters is complicity IMO. I think you did the right thing, it’s just a shame that no good deed goes unpunished.

OP posts: