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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

To tell my sister I don’t like her new boyfriend

173 replies

summerdreams19 · 25/07/2025 12:53

My sister has been dating her new boyfriend for around 10 months now. Initially, I thought he was fine, but I really can’t stand him anymore, and it’s affecting our relationship.

There have been a few incidents, but I’ll share a couple of examples of his behaviour.

For my sister's birthday in June, he wanted to organise a surprise dinner for her with some friends and family. He invited me, providing the time and date, which I accepted. A few days before the dinner, I ran into one of my sister's friends who was also invited, and she mentioned that the dinner had been moved to the next day. She didn’t know I was invited when she told me, and I didn’t mention it to her. My sister's boyfriend never told me about the change in plans, so I assumed I was uninvited. My sister didn’t bring it up, so I don’t think she was aware I was invited either and I chose not to tell her because I didn’t want to ruin her birthday. It’s possible he forgot, but how did he not notice I wasn’t there during or after the meal and why not mention it afterwards?!

Recently, my parents had a BBQ, and this was the second time he met our family. After a few drinks, he became very quiet and distant and wouldn’t speak with anyone (another family member tried to talk to him, but he only responded with one word answers). Eventually, he walked out without saying goodbye to anyone or thanking my parents for the invite. I understand that sometimes people make mistakes when they’ve had a drink, but it’s still early days and he should have been on his best behaviour imo.

My sister has also spent time with his family, and I can’t imagine what they would think if she acted that way.

Usually, I would keep my opinions to myself, but my sister, my nieces, and I spend a lot of time together, and I’ve been avoiding them because he’s always around (either at the house or joining us), and I just can’t bite my tongue or be fake with him. She keeps asking to meet up but I just make excuses.

AIBU

OP posts:
ConfusedSloth · 25/07/2025 14:16

summerdreams19 · 25/07/2025 14:13

Yes, I know why he was upset, my sister told me about it. I was present when my family member tried to speak with him. She didn't say anything that could have upset or offended him. He was upset because my sister called him out on his behaviour.

I've tried to clarify the situation, but it seems you're determined to prove me wrong.

He can't have been upset because your sister called him out if he was upset before your sister called him out. Ye Gods woman!

  1. He was upset.
  2. He was giving one word answers to relative.
  3. He was called out.
  4. He was upset.

Why was he upset at the start? Why was he giving one-word answers? It can't be because of what happened afterwards, can it?

You've not once tried to "clarify" that. At all. You keep saying why he was upset at the end - but not why he was upset at the start.

ConfusedSloth · 25/07/2025 14:18

summerdreams19 · 25/07/2025 14:16

It is quite strange that I was there and witnessed the events, yet I am considered incorrect, while you were not present and yet you are deemed correct and aware of what happened.

What are you on about?

You said you feel uncomfortable. You've also said that it's somehow all his fault.

I don't need to witness anything - you said that. Are you lying?

summerdreams19 · 25/07/2025 14:19

@MarianGrotto

I've been managing those feelings without expressing them, but my sister has asked to see me with him multiple times, which makes me uncomfortable. As it is, this situation is impacting our relationship.

OP posts:
CaptainFuture · 25/07/2025 14:19

summerdreams19 · 25/07/2025 13:19

@ConfusedSloth

None of those things actually happened though. Also, I’m confused about how you concluded that the friend told him I was aware of the date change? She certainly didn’t. The friend didn’t even know that I was invited in the first place (I said this in my original post).

Did you know all the guests who'd been invited?

InWithPeaceOutWithStress · 25/07/2025 14:21

ConfusedSloth · 25/07/2025 13:26

Him: Oh, where's Summerdreams? Oh shit! Did I forget to tell her the change of date?
Cousin: Nah, she knew. I spoke to her about it and she definitely knew it was today.
Him: Oh strange. I wonder why she isn't here...
Cousin/Sister: Don't worry, she's just playing games. She definitely knew about the change of date. Just ignore her - she's always difficult.

Probably what happened.

This. You’re coming across as the problem here OP.

CaptainFuture · 25/07/2025 14:22

ConfusedSloth · 25/07/2025 14:18

What are you on about?

You said you feel uncomfortable. You've also said that it's somehow all his fault.

I don't need to witness anything - you said that. Are you lying?

Agree with @ConfusedSloth and that you sound very dramatic @summerdreams19 !
Does 19=your age?

summerdreams19 · 25/07/2025 14:23

ConfusedSloth · 25/07/2025 14:18

What are you on about?

You said you feel uncomfortable. You've also said that it's somehow all his fault.

I don't need to witness anything - you said that. Are you lying?

At first, he wasn't upset at all. He was perfectly fine. His feelings changed when my sister mentioned that he was being rude to a family member and asked him to cheer up.

I won't be replying to you any further since you're making an effort to undermine me and distort everything I've said. Thank you.

OP posts:
its2025 · 25/07/2025 14:24

I agree with some of the posters. You are coming across as the issue here @summerdreams19
It's de-railed into a debate of who said what at a BBQ.

You said in your opening post that this was just two examples of why the BF behaviour has bothered you.

So to give us a more rounded opinion - what other things have happened that you are concerned about.

DazedAndConfused321 · 25/07/2025 14:24

Are you by any chance single, and now just sad your sister is happy? This sounds so toxic on your end.

Meadowfinch · 25/07/2025 14:25

summerdreams19 · 25/07/2025 13:23

@Hankunamatata

He must have realised after they went out for the meal and I wasn’t there though, so if it was truly an accident on his side, then why didn’t he reach out to me afterwards? I’ve seen him a few times since then. If I were in his shoes, I would have approached the person and said, "I’m sorry, I forgot to mention the date change etc”

But you are expecting everyone to behave as you do, and most people won't. People vary. It doesn't mean they are horrible. They just aren't you.

CaptainFuture · 25/07/2025 14:26

DazedAndConfused321 · 25/07/2025 14:24

Are you by any chance single, and now just sad your sister is happy? This sounds so toxic on your end.

Absolutely my thoughts!

ConfusedSloth · 25/07/2025 14:26

summerdreams19 · 25/07/2025 14:23

At first, he wasn't upset at all. He was perfectly fine. His feelings changed when my sister mentioned that he was being rude to a family member and asked him to cheer up.

I won't be replying to you any further since you're making an effort to undermine me and distort everything I've said. Thank you.

You don't want to reply to me because you don't like that I'm pointing out the problem with your renewed version of events.

If there was nothing wrong at the start, why was he "being rude" and only giving one-word answers for no reason and out of the blue? If there was nothing wrong, why did she tell him to "cheer up"?!

Who says "cheer up" to someone who isn't upset?! That's doesn't sound likely, does it?

summerdreams19 · 25/07/2025 14:26

@Pessismistic

Thank you. You appear to be the only person who understands. Sadly, many women justify men's unacceptable behavior, and this discussion illustrates that.

OP posts:
InWithPeaceOutWithStress · 25/07/2025 14:28

summerdreams19 · 25/07/2025 13:57

@heroinechic

The reality is that my parents share my feelings, so I'm uncertain if we can simply act as if everything is fine. It has become quite uncomfortable now.

You all sound like hard work and lacking in compassion. Hopefully your sister’s boyfriend moves on and finds a better family to join.

summerdreams19 · 25/07/2025 14:30

@DazedAndConfused321 @CaptainFuture

Sadly, my partner lost his battle with bowel cancer four years ago. Does that make you feel better?

I truly want my sister to be happy. She deserves all the happiness in the world. Unfortunately, I have my doubts about this man being a good person.

OP posts:
outerspacepotato · 25/07/2025 14:30

I think you're reaching.

As an adult, you should have checked after you found out there was a change of date. Very passive aggressive move there.

So he got quiet and left after a bit. Maybe he had things going on you had no idea about. Maybe he just wasn't feeling chatty. Maybe he's picking up on your obvious dislike. He showed his face and didn't misbehave. That should be enough.

You guys sound like those men who tell women to smile and get offended when they don't.

Dozer · 25/07/2025 14:33

His behaviour at the BBQ was poor IMO. More context / info would help.

Pessismistic · 25/07/2025 14:33

summerdreams19 · 25/07/2025 14:30

@DazedAndConfused321 @CaptainFuture

Sadly, my partner lost his battle with bowel cancer four years ago. Does that make you feel better?

I truly want my sister to be happy. She deserves all the happiness in the world. Unfortunately, I have my doubts about this man being a good person.

Sorry you went through this I would ignore the haters on here there is no point replying back to them some people just love arguing. I would definitely speak to your sister I would never let a bloke ruin your relationship and your nieces.

MarianGrotto · 25/07/2025 14:33

summerdreams19 · 25/07/2025 14:19

@MarianGrotto

I've been managing those feelings without expressing them, but my sister has asked to see me with him multiple times, which makes me uncomfortable. As it is, this situation is impacting our relationship.

Well, try to move beyond those feelings? The two situations you describe seem like very minor things for you to be this melodramatic about them.

Why were you being so secretive about having been invited to the birthday dinner organised by your sister's boyfriend? You say you didn't tell your sister's friend you'd been invited, you clearly didn't bother to get in contact with your sister's boyfriend to check the date change, you just decided you'd been uninvited. Your sister and her boyfriend presumably thought you'd just failed to show up. That's on you.

And surely, if anyone gets to feel annoyed about the boyfriend's behaviour at the barbecue, it's your sister or your parents, not you?

Cam1981 · 25/07/2025 14:35

I do get where you’re coming from, however the two incidents you have mentioned aren’t enough for me to go to my sister to tell her I don’t like her boyfriend. I would personally be giving him another chance to see what he’s like and also see if my sister has any complaints about him as well. I think if you go and wade in now your sister might want not to confide in you anymore so therefore if he does turn out to be not a very nice person you will have missed the opportunity to help your sister.

ItsNotMeEither · 25/07/2025 14:36

What if you didn’t run into your sister’s friend? But you did! You knew the time changed and didn’t turn up and didn’t call him to sort out the miscommunication. Now that is odd!

As for the going quiet thing, who knows. Maybe he was having a bad day, starting to feel unwell, could have been anything.

Still weird that you wouldn’t sort out the dinner thing for your sister’s birthday.

Agapornis · 25/07/2025 14:36

It sounds like he's essentially moved in after 10 months? How are your nieces dealing with this?

Lambswools · 25/07/2025 14:37

summerdreams19 · 25/07/2025 14:30

@DazedAndConfused321 @CaptainFuture

Sadly, my partner lost his battle with bowel cancer four years ago. Does that make you feel better?

I truly want my sister to be happy. She deserves all the happiness in the world. Unfortunately, I have my doubts about this man being a good person.

I lost my DH 4 years ago. It really does change you, and looking back over the last few years, I've done lots of things that were out of character, and now think wtf was I thinking. I think this will be one of those for you. You'll only hurt and possibly lose your sister if you don't find a way to let this go.

CaptainFuture · 25/07/2025 14:40

summerdreams19 · 25/07/2025 14:30

@DazedAndConfused321 @CaptainFuture

Sadly, my partner lost his battle with bowel cancer four years ago. Does that make you feel better?

I truly want my sister to be happy. She deserves all the happiness in the world. Unfortunately, I have my doubts about this man being a good person.

That's a bit of a guilt tripping statement?

DiscoBob · 25/07/2025 14:40

The things you mention don't sound horrendous to me. But if you get a feeling about him I think you should tell her.

Not in an 'I've decided he has zero redeeming features and you must chuck him now or I'll shun you' kind of way, more exploring how she feels about the way you saw him behaving.

And how he treats her day to day in private. And seeing if she really is happy.