to expect family to use the correct surname for DS?

[cantthinkofadadsname]

My ex and I are separated. DS has a double barrelled surname. He uses my ex's surname at school and that's fine by me as it is a particularly long surname TBH.

My family know it's double barrelled. I don't think they approve but that's their problem. Yet DSIS and my grandma insist on sending him cards with only my surname on it. This really upsets me and my ex and I've told them repeatedly to use his correct surname. They did this when we were together and still do it now.

How many times do I have to tell someone before they get it?

many times I should think if my experience is anything to go by.
I would n't worry too much a bout it though - your DS probably isn't as bothered as you

I don't really see why it upsets you tbh. If your happy for him to use one surname for school then what does it matter anywhere else? You said it's a long surname so it's just easier for them. It's ovb something that really matters to you so I think that your family should do it but I don't understand what your issue is

It upsets my ex. She feels like she's not being recognised and they're deliberately doing it on purpose.

Yanbu my kids are double barreled as well, for ages my mil and dps family only used dps surname on post they sent to the boys, it was really annoying!

What finally sorted it was when ds1 and ds2 werr old enough to notice and they asked why!! Since then post comes with the correct surname on!

she is probably right though - don't see what you can do apart from keep telling them....

I think you made a mistake using just the one for school.

If its ok for school then you can't expect others to understand why you are so upset at home so to speak.

Shouldn't think your child cares tbh.

YANBU.
DH and I were not married when we had DD so for the first 10 months she had DH surname, until we married (as we were getting married I saw no point in giving her my maiden name for a matter of months).
Every single thing my dad sent to her he addressed with her first and middle names only. The cheque he sent, the parcel at Christmas, cards...
I was so upset by this, and I told him so. His response was that she should have had my maiden name as we were not married.
I came to the conclusion my Dad was in fact a caveman!
(Yet his parents - my Gran and Grandad - were absolutely fine with my decision and saw the sense in what I was doing!)
Some people will just decide that they are right, despite all logic, and will be stubborn.
Hopefully your children will start correcting them soon.. I know DS has started to correct people who use a nick name for him, he is 3 and gets really irate with them .