AIBU to refuse looking after my sister's child during her honeymoon?

I would definitely help out and be happy to share with in laws. 8 year olds really don’t need entertainment - at least mine and my neice don’t. Maybe your sister could offer your older kids some babysitting cash to help you out too?

Can’t really pop an 8 year old back up there can she?

I’m surprised they’d leave her for two weeks, seems a bit much all round.

YANBU. When you have children you don’t get the luxury of two week child free holidays. One week with their daughter at her grandparents, sure but asking for two weeks childcare is taking the piss.

Would she have had your children or one of your children for you for that length of time?

Irrespective of that I think 2 weeks is a really long time to leave an 8 year old. They can have a lovely time and relax away from their child for a long weekend or a week or so.

I'd offer a couple of days and suggest the grandparents do the rest / fly out with the child so they get some child free time and some family time.

Out of interest is her new husband, the child's dad? If not I'd be worried she was feeling pushed out

Sorry, but when you have a child, you don’t get a ‘proper’ honeymoon! Not unless it comes with robust childcare that is arranged well in advanced by people who have actually offered.

Being guilt-tripped into being any part of it, is just going to lead to bad feeling.

Poor 8 year old not being with her mum/parents for two weeks at the last minute, just after they get married as well-if I was the parents, I’d be making sure she felt 100% included in family life, not shunted onto exhausted family members at the nth hour before their much-needed summer break.

No, no, no.

How odd to presume you know how a stranger feels.

I second the seconder!! CF’s!

It's MN so the majority will say you're not being unreasonable because on MN everyone is ridiculously selfish and only ever wants to spend time with their DH and kids. But in real life it's unkind and a bit odd that you don't want to have your niece for a week if you're close to either your sister or your niece (or want to be).

You’ve done enough OP! Just say you’ve made plans, had you been made aware sooner etc and directly ask why the groom had not planned childcare for the full two weeks?

How often did your sister help you with childcare when yours were little?

I think if she did have your kids then yeah you should. 2 weeks is a very long time to relax.
But of course you can say no.

Not aimed at yourself. But poor child.

I think the word Shattered is an over exaggeration on your part. Why would you be shattered helping with your sisters wedding and need two weeks off.

Each to their own but I’d try to reach a compromise with your sister about looking after your niece and as others have suggested maybe her in-laws can mind her for a week and you take her the other week.

Tell the truth! You’re exhausted, it’s the end of GCSEs for your own DC and you all took time off to recover.

Your family needs recovery time - maybe the next trip will be better timing for everyone.

Yanbu. Just reply to the sisters in law “oh that’s kind of you to offer! I am sure my sister will appreciate you stepping up. I have so much already planned for my time off after the wedding, and it has been such an exhausting year what with GCSEs and all the wedding planning, i couldn’t manage having DN to stay. It’s lovely that you’re able to complete your parents’ gift by looking after DN.”

How much did your sister babysit your kids? How much babysitting have you done recently?

That's irrelevant. OP has booked time off for herself and her DH and she has plans. There's no way she should be expected to change that. This is where the phrase 'lack of planning on your part does not constitute an emergency on my part'. The in laws fucked up, they can find out.

Once you have children, you need to accept that a wedding and honeymoon won’t be the same dreamy, relaxed, child-free experience you would’ve had before kids.

It’s great if family offers to give you some time off, but the assumption would be that you go away together as a family. Where is the holiday home, why do they have to go for 2 weeks? Perhaps they go alone for a week and child joins them for the second week.

I agree with your husband and that’s exactly what you should say to them.

Who on earth plans this kind of surprise without working out and agreeing the childcare before revealing the surprise? That’s just piss poor planning (or it’s manipulative….)

It would be a no from me too op! Honestly a proper honeymoon? That’s usually something you do before kids …

How much did your sister babysit your kids? How much babysitting have you done recently?

I'd maybe offer a weekend or a day in each week, something to break it up for the in laws if they're older. But definitely not your responsibility.

This

How selfish of him and his parents not to think of the child. That is certainly not a gift, it's a bit of a kick in the teeth. I'd be pissed off with him if I was the bride.

They are being unreasonable. A couple of nights maybe but a week is not reasonable. Also they sound a bit silly when they call it a proper honeymoon given they have an 8 year old child.

This!
your sister needs to get over herself here
her child
her responsibility

Quite. It's not much of a 'gift' if means imposing on other family members, and possibly creating bad feeling. It's fine to ask for childcare but it has to be done in a timely way and allowing the other person to say no - except in emergencies, which this is not.