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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

Original poster

Am I being paranoid about my sister-in-law?

48 replies

PoisedDuck · 18/04/2025 16:10

My sister-in-law (husband's sister) has always been intense, but since I had my (first) daughter 5 months ago, it's gotten worse. She calls herself "Mama number two," refers to my baby as "our girl," and even posted a photo of her on Instagram with the caption "my little one"—without my permission.
She's repeatedly offered to take her overnight, created a photo album using pictures I never shared with her (some from my private Facebook), and set up a nursery at her house—with my daughter's name on the wall.
I'm deeply unsettled.
My husband says she's just excited and means well—but am I being unreasonable to think this is way over the line?

OP posts:
DenimMentor · 18/04/2025 16:11

Yes you are being paranoid. Sounds like free childcare to me. I wouldn't let it bother you.

CurbsideProphet · 18/04/2025 16:13

That is weird. Very weird. Are you testing out the plot to a channel 5 afternoon film?

Calmdownpeople · 18/04/2025 16:13

So what? Unless you feel like she is going to kidnap your child and run away what a nice thing that she wants to try so hard and embrace being an auntie.

Lookuptotheskies · 18/04/2025 16:14

This is way too much.

I'd just call her out on it every time.

She's not your child.

She only has one mum.

How did you get my private photos?

What a lovely nursery, I didn't realise you were expecting..... Oh it's for MY baby, that's .... Odd.

Etc etc.

Original poster
PoisedDuck · 18/04/2025 16:15

I fear my DH would think i'm being rude and unreasonable as he is very protective of his little sister ...

OP posts:
Whattodo1610 · 18/04/2025 16:17

I think it’s very weird and ott. There’s a difference between being a doting auntie and acting like a second mum. My sil did similar, though not with a nursery set up. She couldn’t understand why I wouldn’t let her take my dc to watch a local football match in the middle of a blustery field at 2 weeks old.

ThejoyofNC · 18/04/2025 16:19

It's too much, I'd ask her to back off. You're trying to enjoy your first child and this woman is calling herself mother and trying to take her overnight. It's weird.

Gundogday · 18/04/2025 16:24

I think it’s weird and creepy.

Every time she calls herself Mama no 2, respond by saying her name, ie Aunty Flo, with emphasis on the Aunty.

(I’m hoping this is a troll post, as it’s so creepy)

thepariscrimefiles · 18/04/2025 16:24

She is being ridiculously over the top. Is she married or in a relationship? Does she want to have a baby?

Your daughter is far too young to have a sleepover and your DH should tell her to tone it down. It's fine for her to want a relationship with her niece but she's cosplaying being her mum.

Seventree · 18/04/2025 16:26

God that's creepy, it would really put me off having her around my baby too much.

Original poster
PoisedDuck · 18/04/2025 16:29

thepariscrimefiles · 18/04/2025 16:24

She is being ridiculously over the top. Is she married or in a relationship? Does she want to have a baby?

Your daughter is far too young to have a sleepover and your DH should tell her to tone it down. It's fine for her to want a relationship with her niece but she's cosplaying being her mum.

She has never really been in a serious relationship and has some self-esteem issues - often staying over when she is upset etc ...

OP posts:
Auldy · 18/04/2025 16:31

Not being unreasonable. It's weird. I agree calling her out on it. If your husband thinks you're being rude he will just need to live with that. It's not rude to say "she only has one mummy". You can't do anything about what she does to decorate her own house but you can absolutely limit the time she spends there.

Endofyear · 18/04/2025 16:32

Sounds a bit over the top if you asked me! My sister was thrilled when I had my first baby and did have him for 'Auntie Days' when she would take him out for the day - he was probably 3 before he had sleepovers with her though. She certainly never decorated a nursery at her house or referred to herself as mummy no2! That would irritate me too 😠 I would be firm about her sharing photos etc and tell her baby won't be sleeping at hers until you feel ready which won't be a long time yet!

Babygirlmamahere · 18/04/2025 16:33

That's way too much, I would feel very uncomfortable as well. I'm horrified for you!

DurinsBane · 18/04/2025 16:33

PoisedDuck · 18/04/2025 16:29

She has never really been in a serious relationship and has some self-esteem issues - often staying over when she is upset etc ...

Show quote history

Is she very young? Or older and almost getting to the point where she would not be able to naturally conceive herself?

DriveMeCrazy1974 · 18/04/2025 16:35

You're not being unreasonable. If she wants a child to call her mama, she should have her own child. Your child is not hers and she is not a toy for her to take cute photos of and post all over the internet.
I'd make a point of calling her Auntie every single time she used the ridiculous 'mama number 2' name and I'd be making sure she understood that there would be no sleepovers. Your child is not a bloody toy doll for your SIL to play with!

Hfjfjfjfjfj · 18/04/2025 16:35

Draw clear boundaries and get your husband to put them to her.

Original poster
PoisedDuck · 18/04/2025 16:44

DurinsBane · 18/04/2025 16:33

Is she very young? Or older and almost getting to the point where she would not be able to naturally conceive herself?

Show quote history

She is 28 (DH is 34, I'm 32) so very much able to start her own family but also I would say not young enough to put this down to immaturity, I suspect some sort of attachment issue - though would never bring this up with DH ...

OP posts:
Original poster
PoisedDuck · 18/04/2025 16:47

Endofyear · 18/04/2025 16:32

Sounds a bit over the top if you asked me! My sister was thrilled when I had my first baby and did have him for 'Auntie Days' when she would take him out for the day - he was probably 3 before he had sleepovers with her though. She certainly never decorated a nursery at her house or referred to herself as mummy no2! That would irritate me too 😠 I would be firm about her sharing photos etc and tell her baby won't be sleeping at hers until you feel ready which won't be a long time yet!

I think I will have to remove her from following my account as I just do not feel comfortable with her almost 'stealing' and sharing my photos of my DD as her own!!!!! I do want her to be involved as it would mean a lot to DH and 'auntie days' sound promising but I feel her behaviour is getting out of hand as time progresses

OP posts:
outerspacepotato · 18/04/2025 16:50

She's set up a nursery?

It's time for your husband to deal with his very inappropriate sister. She is not a parent and she's really overstepping boundaries. He's got to drop it on her that she is no way mama 2. Time for him along with you to put up boundaries.

Murdoch1949 · 18/04/2025 16:54

She is being slightly OTT but I think she is just excited about her niece. Talk to her about the posting of photos but otherwise encourage her relationship with your daughter. The more close family members a child has the better. She will be able to develop a lovely aunt/niece bond with your daughter, and you will be able to see that grow. There may well come a time when you are very relieved that there is someone close with whom your daughter feels safe & loved that can quickly step in to help out with emergency care.

yikesnotagain · 18/04/2025 16:56

Nah, that's definitely very... intense. I wouldn't like it either. I kind of had similar from my MIL (some differences, some similarities, but certainly her expectation was that she'd be taking more of a "parental" role than I was comfortable with). It made me feel very anxious and there are certain things she said that I still haven't really gotten over.

I'd probably be expecting my husband to back me up with this one.

Moveoverdarlin · 18/04/2025 16:56

Mama Number 2 would bother me, I would say in a baby voice to keep things passive ‘No! Your Auntie Jo Jo! Aren’t you? Is this your Auntie JoJo? Yes she is! Yes she is. Correct it every time.

Referring to her as ‘our girl’ I could cope with.

HouseCaptain · 18/04/2025 16:59

It is a bit much, but she is excited and she obviously adores your daughter. Would it be so bad if they had a close bond?

thepariscrimefiles · 18/04/2025 17:05

PoisedDuck · 18/04/2025 16:47

I think I will have to remove her from following my account as I just do not feel comfortable with her almost 'stealing' and sharing my photos of my DD as her own!!!!! I do want her to be involved as it would mean a lot to DH and 'auntie days' sound promising but I feel her behaviour is getting out of hand as time progresses

Show quote history

What are your DH's parents like? Do they encourage her behaviour? If you back off and put some boundaries in place, will they be upset with you? It sounds like your DH is happy for his sister to pretend that the baby is hers.