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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

To not be interested in a relation ho with my sister?

57 replies

Pingu99 · 29/01/2026 20:45

edit to say sorry I only just noticed the typo in the title!!

Im going to do my best to share as much as possible here so I hope this is easy to follow!

I’m 26 and the eldest of my fathers children. I have two (half) brothers, who are 15 and 16, and a half sister who is 1.

As is obvious from the above, there are large age gaps between us all. To be clear, my brothers share a mother and my sister has a different mum.

When I was younger I was expected to do a lot for my brothers when visiting my dad. From about age 12 I was expected to make their dinner, clean up after them and generally supervise them for the majority of the time I was there. As such, we have a close relationship now, although it was not always this way as I think my “parental” role meant we clashed sometimes. I feel this was largely down to my dad not standing up and saying it was inappropriate, although clearly my brothers mother is also to blame too.

As time went on I was just the built in babysitter, despite not living with them, as I ‘knew everything anyway’ and I felt a lot of responsibility. They had a rough life, no money and neither of their parents took proper care of them. I have always therefore felt like it was my duty to care for them and help them where I can.

i feel really lucky that I’ve been able to pull myself up by the boot straps into living a good life. I have a wonderful husband, a good job and feel lucky enough to be able to largely do things I enjoy without worrying.

Moving on, my dad married his much younger wife and decided they wanted a baby together.

since they had their baby I have been slated for “having no interest in her”. I will admit I haven’t seen her much (maybe three times) for a variety of reasons.

The summary of those reasons are:

I feel like if I get too involved I will once again be roped into being the free babysitter

I already feel a great duty of care to my brothers (who incidentally my father no longer has contact with) and I don’t feel I can handle another responsibility like this. I do not want children of my own, and I think this is probably due to having to care for my brothers as a child, so I don’t want this responsibility either.

I have my own life now. A life that I enjoy. I’m very close with other members of my family but not my dad nor his new wife. I don’t feel I need this relationship in my life and their child sort of accompanies this.

if I try to express any of this, I get shot down told it won’t happen or told how selfish and horrible I am that I don’t care about my own sister.

im just wondering if anyone things im being unreasonable here? Happy to be told that I am and I need to give my head a wobble!

OP posts:
SandrenaIsMyBloodType · 29/01/2026 20:56

How DARE your father or anyone else call you selfish? How bloody dare he!
I can’t bear that he has you questioning yourself over this.
Tell him if he takes a positive, active role in your brothers’ lives, consistently and not sporadically, then you will do the same for your sister.
That should get you nicely off the hook since offering a consistent, positive relationship is clearly not in his skill set.

ExtraOnions · 29/01/2026 20:56

It’s not your half siblings fault that your Dad is who he is. Try not to lose your sibling relationship, whatever you choose to do.

Aworldofmyown · 29/01/2026 20:53

I would cut the dad loose tbh.

Pingu99 · 29/01/2026 20:53

BigKissByeBye · 29/01/2026 20:51

Surely it’s not either ‘free babysitter’ or nothing at all, though? I mean, I’m not sure what kind of relationship is likely between a woman in her late 20s and her one year old half sister, anyway —what would you like?

I think this is what I struggle with. I don’t know what kind of relationship, if any, I’d want. I’m not maternal and not interested in kids so I don’t really want to play mum in any way, and it’s hardy like we have anything in common 🤣

OP posts:
Ebedee · 29/01/2026 20:52

Not your responsibility. Let your Dad and his wife parent their child.

BigKissByeBye · 29/01/2026 20:51

Surely it’s not either ‘free babysitter’ or nothing at all, though? I mean, I’m not sure what kind of relationship is likely between a woman in her late 20s and her one year old half sister, anyway —what would you like?

ProfessorRedshoeblueshoe · 29/01/2026 20:51

Of course YANBU. I honestly don't know why you have anything to do with your dad. Sounds like he is after a babysitter.

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