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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

My son stopped talking to his sister after finding out she was dating his best friend, and I don’t know how to fix this

676 replies

pilarr · 08/07/2026 10:52

I never thought I would be in a situation where my own children would become strangers to each other.

For context, I'm 46 years old and I have three kids. My oldest son is 19, my daughter is 18, and my youngest son is 14.

My oldest son has had the same best friend since they were 8 years old he is same age as my son. That boy has been part of our family for so long that I never really saw him as just a friend he was almost like another son to me. He was always at our house for dinners, sleepovers, holidays, and everything in between. I watched him grow up.

My daughter also grew up with him. They were the same age, went to the same school, and were always close friends. They would play together when they were younger, and as they got older they would go hiking or spend time together, especially when my son wasn’t around. I always thought they had a good friendship and that both of them were good kids.

About two months ago, my daughter came to me and told me something I wasn’t expecting she and my son’s best friend were dating. They had already been together for two months, and she told me it wasn’t just a small crush. They were serious about each other.

She was nervous telling me. The first thing I asked was whether my son knew. She said no, but she wanted to tell him herself and asked me not to say anything. I felt uncomfortable keeping something from my son, but I also felt it was my daughter’s responsibility to have that conversation with him.

My daughter is a very thoughtful person. She is not someone who makes decisions without thinking about the consequences, so I trusted that she had taken this seriously.

A month ago, my son found out from some friends that his sister and his best friend were dating. What hurt him the most was not only the relationship itself, but that everyone seemed to know except him.

He asked my daughter why she didn’t tell him. She explained that she was scared he would react exactly the way he did. She wanted to wait until she knew the relationship was serious because she didn’t want him to think it was just a temporary teenage crush.

My son was furious. He told her that she shouldn’t date his best friend and that things between them would never be the same. He also confronted his best friend, who tried to explain that he genuinely cared about my daughter and wasn’t playing around.

I understand why my son feels betrayed. His best friend was like a brother to him, and now he feels like that friendship has changed. He has also felt responsible for protecting his sister since their father passed away five years ago.

But I also told him that while his sister should have told him sooner, she did not do something wrong by having feelings for someone she cares about.

I can see both sides. My son is hurt, and my daughter feels guilty. She has cried to me because she misses her brother and doesn’t want to lose him. But my son is still angry and has completely shut both of them out.

It has been a month, and my two older kids barely speak. They act like strangers in the same house. I don’t want this to permanently damage the relationship between my children.

OP posts:
Wickedlittledancer · 09/07/2026 21:41

ThreadGuardDog · 09/07/2026 21:40

Why is it odd ? Yes you may be able to predict the reactions of family members, but it’s not black and white, and not everyone can. I think it’s perfectly reasonable to suggest that DS may have reacted completely differently had DD told him herself. As it was, he was hurt that everyone but him knew about the relationship, and that it had been going on for months - not to mention the realisation that both of them had lied to him throughout that time to cover. So that’s bound to have influenced his reaction.

If DD and BF weren’t bothered about other people finding out - which clearly they weren’t - then they should have considered his feelings and told him themselves. DS has a lot to deal with coming off the realisation that the two most important people in his life thought so little of him.

And your last sentence is rude and unnecessary. We’re randoms on the internet - you know as much about me as I do about you.

Edited

I think it’s perfectly reasonable to accept his sister knows him better than you do. So suggesting you know better is even odder.

ThreadGuardDog · 09/07/2026 22:10

Wickedlittledancer · 09/07/2026 21:41

I think it’s perfectly reasonable to accept his sister knows him better than you do. So suggesting you know better is even odder.

I wasn’t suggesting anything of the kind. Just putting forward an argument in support of DS. It’s a public forum and we’re all entitled to an opinion in a balanced discussion.

ForeverPombear · 09/07/2026 22:19

pikkumyy77 · 09/07/2026 15:33

That isn’t the point she is making @ForeverPombear . Its not that the mother should have betrayed the daughter’s confidence. The point that she is making is that the mother is as “guilty” (if thats the language we are using) of keeping a secret from the ds as all the friend group and the bff but its largely the sister who is coming in for stick.

Yes I get what she was saying but she isn't as guilty as the daughter and her boyfriend. It wasn't OPs place to tell the son.

2Rebecca · 10/07/2026 00:28

I think the son has lost a friend here and this is one of the risks of having a similar age sibling who socialises with your friends. Once you move away this is less of a risk. My brother’s best friend married my sister’s best friend which was weird but didn’t affect my sibs relationship as there was only a year between them. As older sister my brother was unlikely to trap off with my friends. The brother was wrong to feel he should be protecting his sister from whatever he imagines he’s protecting her from but it is a shame she chose his friend. The relationship is unlikely to last but the friendship won’t be the same

Asisaid · 10/07/2026 08:16

pilarr · 08/07/2026 19:21

Of course, they have to be civil and respectful toward each other. I also have a 14 year old son, and he is important too.

Both of them are in university. Since we are in London, there are many good universities here, so they are in the same city. My son also does part-time modelling and works part-time at a luxury travel agency, so he has his own income and independence.

My daughter is currently doing an internship, so yes, they are both doing well.

Your 17 year old is at uni in London?

pilarr · 10/07/2026 08:17

Asisaid · 10/07/2026 08:16

Your 17 year old is at uni in London?

18, read the post properly!!

OP posts:
Asisaid · 10/07/2026 08:24

So both at uni
both in employment
and yet this issue seems to be dominating family life? Or at least your life.

Asisaid · 10/07/2026 08:25

When you say they remain civil etc at home.
So your son is talking to his sister and not stone walling her?

Asisaid · 10/07/2026 08:27

pilarr · 10/07/2026 08:17

18, read the post properly!!

Sorry blame the heat!

ThreadGuardDog · 10/07/2026 08:27

Asisaid · 10/07/2026 08:16

Your 17 year old is at uni in London?

Older two are 18 and 19. OP also has a younger son who’s 14.

Asisaid · 10/07/2026 08:28

ThreadGuardDog · 10/07/2026 08:27

Older two are 18 and 19. OP also has a younger son who’s 14.

Yes sorry

pilarr · 10/07/2026 08:29

Asisaid · 10/07/2026 08:24

So both at uni
both in employment
and yet this issue seems to be dominating family life? Or at least your life.

Huh!

It's called Summer intership what my daughter is doing currently! It's not yet proper job, hopefully you understand that,

My son is working part time at a luxury travel agency, and part time modelling sometimes, he is still in uni

So they are not proper jobs,

Regarding your second question, it make me think that your family nener had an issues

OP posts:
Asisaid · 10/07/2026 08:31

pilarr · 10/07/2026 08:29

Huh!

It's called Summer intership what my daughter is doing currently! It's not yet proper job, hopefully you understand that,

My son is working part time at a luxury travel agency, and part time modelling sometimes, he is still in uni

So they are not proper jobs,

Regarding your second question, it make me think that your family nener had an issues

My point is… their lives are full and busy
and yet this seems to be dominating their lives. I’d have thought they have other priorities!

Asisaid · 10/07/2026 08:32

It is a siblings issue.

It will all calm down.

Just say that you no longer wish to talk about and it’s not to be raised again in the family home.

Are you going away as a family this summer?

pilarr · 10/07/2026 08:33

Asisaid · 10/07/2026 08:31

My point is… their lives are full and busy
and yet this seems to be dominating their lives. I’d have thought they have other priorities!

Exactly!! My son just stopped talking with my daughte, he is keep his priorities on the track

This the real problem here

OP posts:
Asisaid · 10/07/2026 08:36

pilarr · 10/07/2026 08:33

Exactly!! My son just stopped talking with my daughte, he is keep his priorities on the track

This the real problem here

How is giving his sister the silent treatment being “civil and respectful” ?

pilarr · 10/07/2026 08:37

Asisaid · 10/07/2026 08:36

How is giving his sister the silent treatment being “civil and respectful” ?

Wanna checkout yourself?

I will give you my contact and adress, visit our and stay there for a week to investigate, hopefully that Will be possible for you?

OP posts:
Asisaid · 10/07/2026 08:40

This reply has been deleted

Message deleted by MNHQ. Here's a link to our Talk Guidelines.

bigboykitty · 10/07/2026 10:10

pilarr · 10/07/2026 08:37

Wanna checkout yourself?

I will give you my contact and adress, visit our and stay there for a week to investigate, hopefully that Will be possible for you?

Why are you being so rude to this poster who is being perfectly reasonable and has also apologised for misunderstanding?

pilarr · 10/07/2026 10:14

bigboykitty · 10/07/2026 10:10

Why are you being so rude to this poster who is being perfectly reasonable and has also apologised for misunderstanding?

It sounded like interrogative!!

OP posts:
Franpie · 10/07/2026 10:23

You all sound quite highly strung to be honest.

This whole situation doesn’t need to be such a drama.

Happytorepeatmyself · 10/07/2026 17:55

It’s like a low budget US teen melodrama. Only difference is the mother in this one seems way more involved than would if on TV

BunnyLake · 10/07/2026 19:43

pilarr · 10/07/2026 08:37

Wanna checkout yourself?

I will give you my contact and adress, visit our and stay there for a week to investigate, hopefully that Will be possible for you?

Crikey if you’re like this at home maybe conflict is the norm.

kkloo · 11/07/2026 02:19

waterrat · 09/07/2026 21:37

this is about proportionality.

Your son has not been hurt or had anything taken from him that belonged to him - he just feels a bit icked out and shocked.

I can completely understand why your daughter wanted to see how it went before telling him - look at how he has responded! He has been completely disproportionate in his response.

If he loves his sister and his friend he needs to take a deep breath and get over it - is he seriously going to let go of two people he really cares about over not being told immediately?

Op I think you aren't doing your son any favours encouraging his bitterness.

family feuds are very sad, we only live once - he needs to rememebr these are people he loves.

It's been a month, he may well get over it soon, no reason to assume it will end up being a very long family fued.

He doesn't need to take a deep breath and get over it, like with many issues between people often some time passes and the person softens or something naturally brings them back together, he doesn't have to force it.

And if the sister and friend really love him they'll still love him when he comes around.

this is about proportionality.
Your son has not been hurt or had anything taken from him that belonged to him - he just feels a bit icked out and shocked.

At that age their friends are often their life, betrayals or perceived betrayals feel huge, it's not disproportionate to feel that way, it's fully proportionate to their lives, and he is allowed to feel like something has been taken from him.

Werhere · 11/07/2026 18:12

BunnyLake · 10/07/2026 19:43

Crikey if you’re like this at home maybe conflict is the norm.

This.

This must be a family where high drama, screaming matches, cold shoulders and simmering tension probably has been the story since the very start.