To think this isn't nice?

Can you please write your posts clearer?

I think you are saying :

you and partner just moved into a new flat. You are disappointed that your sister/brother won’t visit right away. They will visit in a few weeks when you’re less excited. Your partner is weirdly over invested in all of this and is also annoyed.

If that’s correct, then yes I can understand your disappointment. But it’s a good lesson in people (even family) have their own lives. Don’t let their reactions affect your enjoyment. Your partner’s reaction is odd and he should probably stay out of it. Your sibling’s reasoning, if they specifically told you the reason for not visiting is also a little weird but probably explained through a series of sibling rivalry events you had growing up.

Edited to fix a lot of typos… cat sitting on lap

Think it's because the OP wants to crow 'look at meeee with my wealthy boyfriend! Come pay fealty and let me see your envy, I am younger than you, nnnener nnnener nnnener'?

Mate it's just a house. Get over it. No one else cares. You don't need support.

It's a bit pathetic not to show joy for your sibling having achieved any big life event (baby, new home, marriage, graduation, new job, whatever).

Why exactly do you need her support? In what form do you think support from your sister will help you? With the unpacking?

I was wondering the same thing.
OP why do you think your sister should come and support you? What do you need help with?

And what has your sister's age got to do with the price of fish?

This is now causing tension as the partner of the sister is very annoyed and upset that she will not visit. He feels it is unsupportive and childish especially at her age

So, in summary-your wealthy boyfriend (and you) are pissed off that your sister hasn’t visited your new flat as soon as you move in because you really need her support?

Why exactly do you need her support? In what form do you think support from your sister will help you? With the unpacking?

Partner needs to get a grip!!

He feels it is unsupportive and childish especially at her age

How old is she then?

Do you mean that your partner is annoyed with your sister because your sister hasn't been to visit yet?
TBH your posts aren't terribly clear.

Neither does self-centred, boastful, childish behaviour. 🤷‍♀️

What kind of support do you need, having just moved house?
Tbh you sound boastful and entitled.
I wouldn't rush to visit you either.

god there are family members I still haven't visited years after they've moved into their places, unless it was for a specific event like a housewarming party it's not something I would consider important or necessary.

I think it depends on the situation.

I do think in most cases, we should support each other and be happy for each other even if we are envious that it’s not happened to us yet.

But in some situations it’s ok.

I remember when I was living in one room in a hostel as a single parent and my friend got shitty with me because I wouldn’t go and view a £500k property on her behalf.

If the sibling is struggling then it would be obvious that they would find this hard.

I think it’s quite nasty of you to expect your sibling to be happy for you, knowing that they are struggling.

It doesn’t even sound like you got this from your own hard work, which would be something to be proud of and something your sibling should be happy about.

What is your siblings situation/your situation if this is a reverse?

It’s a bit odd that you’re desperate for a sibling to visit straight away. It’s not a new baby, it’s just a building.

weird

i don't care if someone can't wait to get in & have a look around (just. Ring a box in on your way!) or if they have no interest in having a look about

it's my new place, for me, but I guess mileage varies depending on your need to show it off! I have NO need 🤷🏻‍♀️

Wouldn't bother me in the slightest, why does someone moving house need
support?

But why does the sibling who has their own place need 'support'? They're not grappling with a difficult situation, they're in an enviable position. The sibling who can't yet afford their own place is communicating clearly that they're struggling slightly about it all, but will; visit in a little while. Equally possible to think that the sibling with his/her own place could show some sensitivity in response.

I have two single siblings and two married/longterm partnered ones. The three of us who are married/coupled up have much bigger homes and got them earlier, because there were two of us contributing to a deposit and paying a mortgage. It can feel very unfair.

Entitled behaviour doesn't look good either.

No one owes you their support or good wishes just because you have a partner who earns more money.

The new house/flat isn't going to go stale if everyone doesn't visit before you've finished taking stuff out of the removal truck! They haven't said they'll never visit, they're communicating with you.

My sister and I wouldn't get into petty squabbles about something like this, no.

why do they have to visit the new place immediately? why does someone have to drop everything and rush to a siblings 'new place' just because its new?

i have 4 siblings, i have lived in my house 11 years.. 2 of my siblings have never in all that time visited. the world did not end

I couldn't get worked up about this... not visiting a new baby maybe.

They have shared their feelings. Take it at face value and shrug it off.