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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

Original poster

Man I have been seeing for months has fiance

195 replies

Larose123 · 17/03/2026 01:40

Im completely head over heels for a man, we've been seing each other for three months. He's a lovely man, so funny, kind, caring, intelligent, ambitious etc

Today I found out he has a fiance.

He doesn't know I know.

What do I do?

I'm not even angry with him, I just feel numb right now. And sad 😔

OP posts:
WonkyMirror · 17/03/2026 01:42

Dump him and move on. He has proved what type of man he is, what more proof do you need?

Original poster
Larose123 · 17/03/2026 01:42

@WonkyMirror Do i tell HER?

OP posts:
Farewelltothatid · 17/03/2026 01:44

Perhaps you should find some anger OP.
He has taken you and his fiance for fools.
And yes. You should tell her.

Ophir · 17/03/2026 01:45

Oh, that’s horrible @Larose123

I feel for you. The only thing to do is dump
him and grieve and move on. I’d tell his fiancée too as I’d want to know but that’s up to you.

Original poster
Larose123 · 17/03/2026 01:45

@Farewelltothatid You are so right! I hope I can find my anger. Its not there right now. I feel grief

OP posts:
NoCommentingFromNowOn · 17/03/2026 01:47

Larose123 · 17/03/2026 01:42

@WonkyMirror Do i tell HER?

Lots of people here would say no. Even a few days ago I saw someone say she would ‘not thank you for interfering in her marriage’.

However, what would you want if the situation was reversed? If your fiancée had been seeing someone for three months, then she realised what was going on, would you want to be told? Or would you rather be in ignorance, unknowingly exposed to STIs and all the rest?

Original poster
Larose123 · 17/03/2026 01:48

@NoCommentingFromNowOn I would want to know!

OP posts:
ImFinePMSL · 17/03/2026 02:11

A lot of people on here will say “no don’t tell the woman, just block him and move on”. Which is probably the most sensible and dignified thing to do.

But in shocking and heartbreaking times, we don’t feel like doing sensible or dignified things. We want to do the opposite. We want to be irrational.

If you want to hurt the bloke and fuck his life up, get revenge - don’t tell her. It won’t make this situation hurt any less.

If you genuinely want to woman to know, so she can make her own decision - tell her. But make sure you have evidence. Call logs and text messages with dates and times of meetings. But be prepared for any drama. You know “shoot the messenger” and all that.

You don’t have to do anything right now. Let the hurt and shock sink in first.

NoCommentingFromNowOn · 17/03/2026 02:13

Larose123 · 17/03/2026 01:48

@NoCommentingFromNowOn I would want to know!

Agreed, I would ALWAYS want to know. Imagine it, people knew, maybe your friends knew, maybe neighbours, maybe relatives, and you’re stuck with ‘well I wouldn’t thank them for interfering in my marriage’ and….somehow being okay with that?

Original poster
Larose123 · 17/03/2026 02:19

@ImFinePMSL No you don't understand. I dont want to to hurt him at all. And I can't come to terms with it. I feel this is more irrational than wanting revenge. Revenge would be the rational thing to want.

OP posts:
GarlicFound · 17/03/2026 02:20

Who cares if she 'would thank you' or not? You'd have said if the fiancée was in your close circle of friends/family. She's a woman who has one thing in common with you: you were both duped by the same lying rat, who's evidently very good at manipulating women's affections. That already marks him as a user and a misogynist.

I'm really sorry you're going through this. Yes, do tell her - and, yes, do make it as detached, factual and well-evidenced as you can.

I hope you have good people around you Flowers

Original poster
Larose123 · 17/03/2026 02:21

@NoCommentingFromNowOn I would want to know. Shes planning her future with a man who has no respect for her. Disgusting.

OP posts:
ImFinePMSL · 17/03/2026 02:22

Larose123 · 17/03/2026 02:19

@ImFinePMSL No you don't understand. I dont want to to hurt him at all. And I can't come to terms with it. I feel this is more irrational than wanting revenge. Revenge would be the rational thing to want.

Sorry, what is it I don’t understand?

Original poster
Larose123 · 17/03/2026 02:24

@GarlicFound This is so messed up! I feel like if I tell her then Im betraying him. What THE HELL IS WRONG WITH ME?

OP posts:
NoNever · 17/03/2026 02:25

He’s not a lovely, kind caring man. He’s a liar and a cheat.

I think you should tell her. Let her escape BEFORE she marries such a horrid man.

UnderMyOwnVineAndFigTree · 17/03/2026 02:27

I'm sorry this happened to you.
I'd be wary of further discussion with him -he's likely to have an answer for this scenario and as you sound (understandably) as if you've been absolutely smitten with what seems to be quite a delightful package (bar the bastard lying and nasty cheating), he could perhaps suck you back in again.

As for his poor fiance -please let her know. He had no compunction about cheating on her with you, and might do it to her again. The poor woman. Write her a kind message, make it clear you had no idea he was engaged and that you broke off contact as soon as you learnt the truth. Say you're sorry (even though you weren't to know) for becoming involved with her fiance and for being the one to bring such a bombshell into her life now.

SomethingUniqueThisTime · 17/03/2026 02:39

You have no obligation to tell his fiance, there isn’t really anything you owe her or him.
Do what works for you best, give yourself time to grieve the relationship you thought you had. You’ll probably be seeking some form of closure, in order to move on. Trying to understand will drive you a bit mad, but focus on the man you thought he once doesn’t really exist, his values are not the same as yours.

Kettless · 17/03/2026 02:43

Lying cheat.
Definitely let her know.
He is not nice at all.

NeedyTiger · 17/03/2026 02:46

Larose123 · 17/03/2026 02:24

@GarlicFound This is so messed up! I feel like if I tell her then Im betraying him. What THE HELL IS WRONG WITH ME?

Or are you wanting to tell her in the hopes she leaves him and you are free to be with him going forward ? And that's why you think this would be a betrayal to him and he will see it this way ? 🤔

mediating · 17/03/2026 02:49

Knowing how awful the divorce process can be, especially when ones spouse is dishonest, I would say please give her everything she needs to help her avoid getting married to him.

angelfacecuti75 · 17/03/2026 02:55

Op you are feeling shock atm .
This man isn't the man you think he is...he's a scheming, smarmy charmer with the gift of the gab who took you and his fiance for a ride.
I think you need to deal with your own feelings before deciding what to do about his fiance.
Revenge is a dish best served cold & all that.
At least you have the chance of bigger and better things, whilst the 'OW' (for brevity) is gonna end up with the chump for life...m

NotMeAtAll · 17/03/2026 03:05

I tend to lean towards not interfering in someone else's relationship, but in this case she needs to know before she marries him.

Enrichetta · 17/03/2026 03:08

Larose123 · 17/03/2026 02:21

@NoCommentingFromNowOn I would want to know. Shes planning her future with a man who has no respect for her. Disgusting.

For this reason if no others he deserves to know.

What she does with the information is up to her.

WhatTheHellsGoingOn · 17/03/2026 03:18

Larose123 · 17/03/2026 02:24

@GarlicFound This is so messed up! I feel like if I tell her then Im betraying him. What THE HELL IS WRONG WITH ME?

Just remember he’s sleeping with her regularly and planning a future with her. That should dislodge any loyalty you have towards him.

Sweetbeansandmochi · 17/03/2026 03:19

Agree completely with @angelfacecuti75 .

The grief you are feeling is for what you projected into the future- here he is/was. The chance for someone to build something lasting with, someone to be on your side, and it’s so understandable as it’s what many of us want.

Beware of him trying to charm his way out and you wanting to believe him.

Even if says you are the one, elevated above his fiancé because you connect with him on a deeper level, or whatever he might say to you- remember he asked a woman to marry him. He promised to, to say yes to her and no to everyone else for the rest of their lives, and that is a choice not a feeling.

Therefore he has shown you who he is behind the words. You know it. You have had a lucky escape by finding this out relatively early.