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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

ADVICE NEEDED - Ex doesnt want to tell our child about his secret baby

103 replies

GoldenTiger · 27/09/2025 23:41

I separated from my ex partner who then began dating my best friend for a short while and they are now pregnant with his child. My ex wants nothing to do with this child, so has decided he isnt having any involvement, he no longer talks to my friend who is due to give birth soon.

My ex had said he is not telling our child about their half-sibling and that I have no right to tell them either - our child is 8, he plans on them never finding out. However, I have numerous other close friends who know about the baby and their children know about the baby and the pregnant friend lives a very short drive away. I'm fearful for our child's mental health should they find out through someone else or through another child talking about it to them, as I feel this is likely. I have said to my ex that they need to tell them due to my concerns of someone else telling them and the betrayal they might feel because of it. It's breaking my heart for our child because I feel they should know, I don't want them to feel I've hidden something from them but their dad won't allow me to. He has been emotionally aggressive and physical aggressive in the past, no physical harm to me or our child but has hit things in our home, which is why I left the relationship which makes me worried about telling our child when he's saying no.

Please can someone offer some insight or advice, any thoughts or opinions would be much appreciated.

OP posts:
Ponoka7 · 28/09/2025 10:05

Motomum23 · 28/09/2025 09:06

Will you and your friend (ex-friend?!?!) Facilitate a relationship between the half siblings?? If so then I would tell him but if not then it would be cruel to tell him.

Much more cruel to find out years down the line that your Mum unnecessarily kept that information from you, or worst case scenario, that you've had sex/live with your half sibling.

zazazaaar · 28/09/2025 10:07

Thanks to dna testing i now have 3 friends with surprise siblings. They have all found it a shock but the one who was most hurt was the one who had been lied to by her mum. She had a bad relationship with her Dad (who was the parent of the new found sibling) so that wasn't damage as already shit but was very very hurt by her Mum.
These things come out. Someone will tell your child if people know. It would be very hurtful to find out of someone else.

DaisyChain505 · 28/09/2025 10:08

He’s already proved what a shit person he is and thus behaviour just follows suit.

Your child absolutely has the right to know they have a sibling and even if he tried his best one day they would find out whether he likes it or not.

As much as it may hurt I would get in touch with your ex friend and state that you want the siblings to see each other because they are who is important in this whole shit show.

Ignore your ex and put your child first.

MatildaTheCat · 28/09/2025 10:09

An ex doesn’t get to dictate what you do.

Secrets and lies are toxic. If you genuinely think your child should be aware and will cope at this point with the information then talk to your ‘friend’ and discuss options.

Are you still friends? Will the children be part of the same friendship group? What does she want as regards a sibling relationship?

I would think through as many scenarios as possible before saying anything because there are a lot of variables but 100% be honest with your child. One lying parent is plenty.

Blushingm · 28/09/2025 10:11

If you all live locally, in 20 years time they could be on a night out and bump into each other and possibly start a relationship - they need to know about each others existence

BeccaSouth · 28/09/2025 10:13

Blushingm · 28/09/2025 10:11

If you all live locally, in 20 years time they could be on a night out and bump into each other and possibly start a relationship - they need to know about each others existence

Very true. Better to find out now.

MikeRafone · 28/09/2025 10:14

You don't have to follow his "rules" its perfectly ok for you to formulate your own.

Is it likely that this sibling is likely to be leaked by on of the group of friends?

Does your ex still have regular contact with their father?

MikeRafone · 28/09/2025 10:15

Blushingm · 28/09/2025 10:11

If you all live locally, in 20 years time they could be on a night out and bump into each other and possibly start a relationship - they need to know about each others existence

Indeed - sibling attraction is a known phenomenon, when they have grown up apart

Greenwitchart · 28/09/2025 10:17

Tell your child who has a right to know they have a half sibling.

He is your ex and a complete failure as a man and as a father who should not be listened to.

Seelybee · 28/09/2025 10:21

Beeloux · 28/09/2025 09:34

I would have been very upset if I found this out by a peer at 8. Much better OP tells them herself.

But being upset doesn't constitute damaged mental health for an 8 year old. Honestly, it's such an abused term. Being upset/sad/ depressed/worried to a degree about life events is a normal part of life and contributes to building resilience. Which seems to be sadly lacking in our society given the massive rise in people who apparently can't work because of 'anxiety and depression'.

Wtafdidido · 28/09/2025 10:21

sod your ex he has already proved himself to be a selfish arse and not telling your so. Is purely him not wanting your son to think badly of him for cheating. Personally I would put any grievances aside and speak to your friend/ex friend and say that you would like your son to to be able to have a relationship with the baby as it is his half sibling. If she agrees and you can work it out the you should tell your son. If she does not agree then telling your son will
at this stage only cause him hurt and damage I. Which case I think you have to wait til he is older and tell him and explain that you did your best to try and facilitate a relationship but it just wasn’t possible and if he decides to try for himself support him and be there for him. I’d let your ex go to hell with his opinion.

JLou08 · 28/09/2025 10:30

Your child deserves to know who his siblings are, even more so when they live so close and he is likely to find out from someone else. Surely it's better hearing it from a parent than in the school playground.

MNLurker1345 · 28/09/2025 10:35

You must tell your DC. It is only by way of adults, after acrimonious relationships and breakups complicating things, that children are hurt and confused.

This matter is between you and your child. The way your ex handles it with DC, is up to him,
but it is your duty to protect your DC from the toxic behaviour of his father, from the gossip of others and to try if possible (when the time is right), to allow your DC to have a relationship with half sibling. No guarantees though!

You know that you are under absolutely no obligation to do what your ex says. You are also under no obligation to discuss this with him either. He has lost any rights on this due to his behaviour and he is your ex.

The children come first!

Zempy · 28/09/2025 10:37

He doesn’t get to tell you what to do!

Tell your child the truth. I am assuming they know your “friend” so just say Sarah is having a baby in January and daddy is the baby’s father. That means the baby will be your half brother or sister.

Your DC will surely have friends who have half siblings. Do you intend to facilitate a relationship between the siblings? I probably would.

JLou08 · 28/09/2025 10:37

Seelybee · 28/09/2025 10:21

But being upset doesn't constitute damaged mental health for an 8 year old. Honestly, it's such an abused term. Being upset/sad/ depressed/worried to a degree about life events is a normal part of life and contributes to building resilience. Which seems to be sadly lacking in our society given the massive rise in people who apparently can't work because of 'anxiety and depression'.

You don't think it's wrong to keep it from a child that they have a sibling?

Slipperhead · 28/09/2025 10:43

Talk to Women's aid and consider the police.
This is a coercive abusive ex partner.
Absolutely tell your child. They will hear about this, without a doubt.
No way would I tolerate the opportunity for them to hear about this from someone else.

You feel threatened by him.
You need advice, support and report him.
HE doesn't get to control what you tell your child.

thepariscrimefiles · 28/09/2025 10:43

OP, do what you think is best for you and your child. Don't worry about your ex or your friend who have shown no loyalty to you.

As so many people are aware of theh situation, I think you should be the one to tell your child, just in case he finds out from the children of the people your ex-friend has told about it.

You ex-DH is a twat, so I wouldn't worry about upsetting him and your 'friend' isn't much better.

Slipperhead · 28/09/2025 10:50

It has never ceased to amaze me, the stories my children have brought home from school. Really private family business that children overheard and then in their innocent repeated in the school yard.
My two daughters were absolutely brutal for it.
I knew far too much about the drama's, affairs, finances losses, in other highly respectable, affluent homes.
Unbelievable stuff.

So OP, get infront of this and explain it to your daughter in a very calm, no dramatic way.

A very good statement to say is "Adult relationships can be very complicated and difficult to understand when you are very young"

Assure her that life will not change for her and you love her very much.

Wishing you strength.

GoldenTiger · 28/09/2025 10:50

Seelybee · 28/09/2025 10:21

But being upset doesn't constitute damaged mental health for an 8 year old. Honestly, it's such an abused term. Being upset/sad/ depressed/worried to a degree about life events is a normal part of life and contributes to building resilience. Which seems to be sadly lacking in our society given the massive rise in people who apparently can't work because of 'anxiety and depression'.

Unfortunately it can, as a Mental Health professional I've seen mental health issues in extremely young children. I'm fully aware of the mental impact that can result from lies, yes they can just be upset or it can cause long term damage to parental relationships when they feel they can't trust a parent which is what I want to avoid. I also mean the MH impact it could have in the future, a child might think nothing of finding out through others, but as a teenager, finding out then could destroy any trust and have them doubting everything.

OP posts:
BeccaSouth · 28/09/2025 10:53

Slipperhead · 28/09/2025 10:50

It has never ceased to amaze me, the stories my children have brought home from school. Really private family business that children overheard and then in their innocent repeated in the school yard.
My two daughters were absolutely brutal for it.
I knew far too much about the drama's, affairs, finances losses, in other highly respectable, affluent homes.
Unbelievable stuff.

So OP, get infront of this and explain it to your daughter in a very calm, no dramatic way.

A very good statement to say is "Adult relationships can be very complicated and difficult to understand when you are very young"

Assure her that life will not change for her and you love her very much.

Wishing you strength.

I agree - my DD knew everything about the private family matters of most people in her class. I’m also a primary school teacher and children talk openly about everything they’ve heard at home/in other children’s houses.

LIZS · 28/09/2025 10:53

He can’t stop you telling your child anything. Now might not be the right time though.

Sporadica · 28/09/2025 10:55

He can't have nothing to do with the child unless he's planning to move abroad for the next 18+ years; he'll be on the hook financially (and this may impact you too if you're receiving CMS). You've done the right thing giving him the chance to tell your child first but he has now said that he won't. He can't forbid you to tell her and he's delusional if he thinks she'll never find out!! Even if you agreed it was best not to tell, if the mum and others your child has contact with are being open about who the dad is your child is going to hear it soon enough anyway. In this specific case I don't think I'd necessarily proactively tell her but I also wouldn't deny it if she asked about it.

GoldenTiger · 28/09/2025 11:03

Sporadica · 28/09/2025 10:55

He can't have nothing to do with the child unless he's planning to move abroad for the next 18+ years; he'll be on the hook financially (and this may impact you too if you're receiving CMS). You've done the right thing giving him the chance to tell your child first but he has now said that he won't. He can't forbid you to tell her and he's delusional if he thinks she'll never find out!! Even if you agreed it was best not to tell, if the mum and others your child has contact with are being open about who the dad is your child is going to hear it soon enough anyway. In this specific case I don't think I'd necessarily proactively tell her but I also wouldn't deny it if she asked about it.

He's refused to pay CMS, and has 'lost his job' after threatening to quit it if I went via CMS. He doesn't contribute financially at all to our child, everything is on me, which luckily I'm more than able to do so I doubt friend will see a penny either as he's now unemployed.

I don't actively see friend anymore but even he has bumped into her with our child whilst she's been pregnant, she wasnt showing much at the time so pur child never questioned anything. So it shows we live in a small enough place for it to happen.

OP posts:
BeccaSouth · 28/09/2025 11:06

GoldenTiger · 28/09/2025 11:03

He's refused to pay CMS, and has 'lost his job' after threatening to quit it if I went via CMS. He doesn't contribute financially at all to our child, everything is on me, which luckily I'm more than able to do so I doubt friend will see a penny either as he's now unemployed.

I don't actively see friend anymore but even he has bumped into her with our child whilst she's been pregnant, she wasnt showing much at the time so pur child never questioned anything. So it shows we live in a small enough place for it to happen.

What a prince. You’re well rid of him.

JFDIYOLO · 28/09/2025 11:07

You will have to live with this dark lump in your heart if you keep his secret for him.

And then when your child is old enough to discover that they have a hidden half sibling, that their own father disowned their own child ... and that YOU KNEW (and they will find all this out) ... Nuclear.

Imagine the reading of the will and an unknown sibling suddenly turns up to challenge.

Tell your child now. Age and individual-appropriate language, of course, keeping your emotions and opinions of ex's behaviour, your tone and expression under strict control. A casual, simple mention, ensuring they know they can ask anything they feel they need to.

Your ex is a controlling arsehole. But you already know that.

He will need to know your child knows - it can't come as a surprise in conversation with them.

I'd say send ex a formal email setting out what you have told your child. And never be alone with him.