To not want to give my DSD the money we would have spent on her holiday

Ds19 didn't come on our family hol this year, it was a big one (he had the option) we did help him out on his hol instead with friends though. He didn't demand it we just thought it was fair he just finished exams & probably heading to uni if all goes well. And shocker we will help him through that too somewhat.

I went to Disney with my family at 18 and had a great time!

It absolutely is, up to age 23 or end of uni, whichever is first. That's comimg from a sixth form college teacher. You are 100% wrong about this. He's a complete and utter shit if he doesn't send her any money while she's at uni. The full maintenance loan has fallen WAY behind the cost of living. Fwiw I agree with you about the original issue. The best argument I've read on this thread that applies to the holiday is: if you invite someone out for dinner and they decline, you don't send them £50.

I'm with you @PhaedraTwo

There is a steely (and almost self-congratulating) unkindness that manifests toward stepchildren in many of these threads, and, while I am not a stepchild myself, I find them really disturbing.

Sounds fairly normal to me.

Wonder how many groups of 18 year olds can pay for that

You are talking absolute rubbish

No. That's crazy. The money isn't a gift. The experience would have been the gift. Tell her the greed shown by her abuse just confirms the rightness of your decision.

To be frank, I don’t find your SD completely unreasonable. You are going on holidays with your DC in mind so that’s why you chose Disneyland. You didn’t offer to change destination to accommodate what she wants too and she refused to join. It is always hard to be the kid that just needs to tag alone with the “main”family. I appreciate it’s annoying but it will be nice if your DH gives her some money to go on holidays with her friends or spends them as she like. And to all the people that they will say she is 18 years old, she is an adult, she can have her own money etc. Have you seen the job market?! It’s tough to even get a retail job. So be more understanding.

The problem is that they didn’t have a family discussion including the SD and all agreed to go there. They clearly decided to go to Disneyland with the younger kids in mind. It would have been thoughtful to discuss it as “one” family and agree on the destination. If then her SD didn’t want to join anything, rightfully so not to give her money.

You obviously haven't read the OPs post else you would know she had a job, which she will continue at uni as well as getting full loan etc. And has not long come back from a trip to Ibiza with friends

The next child down is 14 so not THAT much younger. The way you are talking is as though they planning things for a 5 year old

The 14 year old didn't " choose" either

They are younger than the SD and they are in a different stage of life. I bet if this girl was her own daughter and not her SD, they would have decided altogether where to go on holidays and everyone would have a say like families usually do.

Why do you think that? I certainly didn't given my own kids free rein on where they wanted to go. Most I did was choose a couple of places that I liked and see what they'd prefer ( mind you whatever one said the other would want the opposite) And for example I had kids of 16 12 and 4 together

And seeing as the other 2 kids weren't asked either they were treated equally

Just block her and her Mum- you had no need to offer to take her with you, and there is no reason why you should give her the money- who on earth does she think she is?

Is it usual for everyone to get a say?

My children certainly don’t get a say in where we go on holiday. My husband and I don’t sit down with them to come to any kind of agreement. We, the adults who are paying, decide where we go on holiday.

We are obviously aware that we have children, and factor that in. But if I wanted to take them on holiday to Disney, and one of them said they didn’t want to go, they would just need to deal with it. Not that they would react like that anyway. There are 3 of them, and they understand that not everything will be centered around them individually all of the time.

I feel like it’s only really stepchildren who are given inappropriate levels of decision making and control in situations that ordinarily children in intact families just go along with. It’s really, really weird.

Absolutely this.
And they aren't even embarrassed to behave like this

Erm…I beg to differ. Mine is 18 and coming with me (39) and husband (42), plus my mum (67).

We also went with my in laws last year which included an 8 and 13 year old…we had a whale of a time.

Older teens don’t like theme parks now?

Have you been recently? It is full of huge rollercoasters that didn’t exist 20 and 30 years ago when the only place you could go big was Busch Gardens…My 18 year old would disown me if I tried to go without him.

Speaking as a wicked stepmother [but not really a stepmother because the kids were adults when I came into the equation], I'd say that you can find yourself in a situation where you don't want to cause a rift between your husband and his children and you tend to put up with more than you would normally do as a result.

Possibly not the same, in that I've only dealt with adults [and their partners], but the desire not to rock the boat is the same. There were times that I'd have called them out for thoughtless behaviour, but really felt that I couldn't. (With hindsight, I should have done.)

However, in the example in this thread it's the husband's ex who is interfering with things and yes, I do know that feeling well.

Again, in the interest of not rocking the boat and not wanting to muck up familial relationships, I tolerated more than I should have done.

I can understand the OP's relief at the prospect of no longer having to deal with the ex, but it's not always that simple.

An 18-year old girl about to begin university is, for all intents and purposes, far more than 4 years older than her half-sister of 14 (with whom she does not live, nor presumably has any sisterly bond been established).
A girl that age is very much looking ahead, where age is concerned, not backwards to the early teens.

why are we presuming no bond?

If it is to Disneyland Paris probably quite a few. Lots of students go to Ibiza etc together and you only need a day , maybe two if you are keen to go. It's common in the US for graduation groups to go - which being more local makes it more affordable.

But frankly I agree with you and that reinforces my point that it isn't really on the radar of a lot of 18 year olds, and not really a top trip choice for many once they reach that age.

It’s not DLP it is WDW

I agree with you. Poor kid is regarded very much as an outsider by the sound of it, and her not fancying three Disneyfied weeks with her dad’s main family is scarcely to be wondered at, for umpteen reasons (principally, I don’t doubt, because Disney holds no allure for her at all, and she has much to do over the Summer anyway)
It’s rough that she’s copping the trickle down disdain held by OP re her mum. (She is referred to often in the thread as though her mother’s bad moves or other irritations were in fact her own, and one has to wonder how successful OP is, in treating the DSD without prejudice. There seems to be much bitterness flying about)

I do hope her dad will slip her a couple of hundred quid to boost what she’s saving up, since it sounds like his three weeks among the cartoons is being paid for.