To want to do something with just my kids?

Yes i suspect this is a Mother (and father) who just like the sound of a week with their child in someone else’s care…

And yet her DH has been for many years, and has been happy for OP to help raise his daughter for more than a decade.

God forbid a mother wants time with her own children!

The problem here is not OP or DSD. The problem here is the ExW feeling her child is entitled. Why can't she take DD away when OP is away? Then it's fair for all the kids, if fairness is what ExW is concerned about.

I find the notion of being “family” and therefore needing to be together ALL the time so odd. It doesn’t even happen in bio families. Some kids have shared hobbies, like fishing trips with only one parent. I relish the opportunity to have a day trip with just one child.

Yanbu. If your husband ie her dad was coming then that would be different. You have no obligation to take her on your own.

Perhaps to you, but I had this question too and it matters to me.

You're not being selfish or unreasonable.

What you do with your children is your business, not ExW's. If DH was going as well, I could see her point. But he isn't.

ExW is out of order to even ask the question. She should have shut down the conversation with DSD by saying 'LilyPanda is taking her children away alone, your dad isn't going. Just like you get holidays with just me, her children should be allowed holidays with just their mum'. End of conversation.

This is a stretch, even by Mumsnet standards!!!

It's fine OP. You are a family in your own right. It's great to take your children away for some 1:1 time with you.

No not selfish, it is important to have qauilty time with your children.
The mother of the girl can make her own plans with your or her dad.

She is either part of your family or not.
The argument that her mum doesn’t take your kids on holiday is ridiculous, your kids are not enmeshed in her mums life.
That said, being responsible for a 16 year old abroad is a big ask. I would want DH there too.

I don't think you need to treat children the same. I take my own children away on different trips to eachother due to age gaps, interests and simply the fact I can't afford to take them all at once (single parent).

Just pitch the holiday as being for younger children when talking to step daughter and her mum. It also get harder to book accommodation with more children in tow especially in hotels where nobody really wants to share a bed.

I don't think yabu at all. I never took DSS on a holiday without his Dad. I can't believe the Mum even asked. Perfectly reasonable for DSD to want a trip with her Dad at some point.

It's fine for you to take your kids away.
Make sure DH has something fun to do with his daughter when she visits while you are away.
Send her a post card and bring her back a gift.

I would only do this if the holiday could be organised when DSD is with her Mum. Expecting her to sit in your house alone all day while her Dad is working and she knows her siblings are off on holiday is cruel IMO.

I understand you wanting to spend quality time with your own DC. But the fact that DSD wants to come on the holiday suggests she wants to feel included, which is not unreasonable. There will naturally be some jealously that your DC's get to have both their Mum and their Dad with them full time and she doesn't. The holiday does sort of shine a light on the fact that you don't see her as part of your family even though you've been in her life for as long as she can remember.

Can your DH take DSD away somewhere just the two of them? Even if it's just for the weekend?

DSD's Mum should be keeping her opinions to herself. It's not her decision and even if she feels YABU she shouldn't be making a big deal of it in front of your DSD as that will make her feel even worse.

I agree with all of this. I just think that, if the dad is paying for a holiday for some of his children, he should pay for a holiday for all of his children. I'm not saying that the OP should take the dsd. Merely that her dad should be fair to all of his kids.

Of course, if he is already paying very generous amounts of maintenance over and above the minimum requirements, it might be reasonable to suggest that the mum takes her dc on holiday with that.

Stepmum here. When you marry a man with children, you have a ready made family - and subsequent children just make the family bigger. Relationships are not equal but you can and should do your level best to treat the family children equally. Your SD is likely to view this as being treated as 'lesser' - your biological children will learn they are 'better'. Neither of these are good things to teach your family children.

This!!!

Re part one, of course you can. Have schools near you never run a French trip or similar?

I think it is perfectly reasonable for you to take your two children away for a few days on your own.
It is none your your partners Ex's business what you do with your children.

This. I’d always take my DSD. But very few people on mumsnet ever agree with this perspective.

Up until this point I sympathised with wanting to have time away with your own kids, but could see both sides.
However with this age gap I don't see how it would work. There is a huge difference between what a 16 year old likes and what a 12 year old likes. And a 16 year old could bring all sorts of challenges.
It's not like they are 4,5 and 9.
I'd explain to DSD that you are doing really kiddy stuff on holiday and she wouldn't enjoy it.

Also what usually happens with holidays when your DH goes too, do you take all 3 children or just your shared pair?

No, it doesn’t. It sends a message that while they are family, OP isn’t her mother. The length of time OP has been in her life is irrelevant - she isn’t her mother and there’s nothing to suggest she’s ever taken on that role. Same way as she goes on holiday with her own mother and without her half siblings, OP and her kids get to do the same.

None of which should be news to the stepdaughter tbh.

From your DSD point of view, this very clearly sends the message that she is not part of 'your' family. I think it would feel very upsetting and cruel. Especially as she has been a part of your life for so long. I wouldn't expect her to show any concern or loyalty to you on the future - teenagers have very long memories for these sorts of slights.
As others have pointed out, as a 16YO she probably would have declined an invite anyway, but deep down extending an invite to her would have meant a lot.
The ex wife is probably not stirring the pot, but it is more likely that DSD has expressed her hurt to her mum.
I feel sorry for DSD.

No it’s fine to go away with just you and your kids.

But if I was the dad I would be feeling guilty that she feels so upset and so I’d be doing something special with her when you go away.

Can he take a day or 2 off and take her somewhere either over night or just day trips?
It will be nice for them to have 1-1 time too.

This is what I'd do