I grew up an only child, whereas DH has 2 brothers who are both married with kids. We all live in London but different areas and we're fairly close for a family.
I would describe DH and I along with BIL & SIL 1 as middle class, not massively wealthy but well off enough, decent mortgage etc. Neither of my SIL's work but I do, so they're a lot closer as they spend a lot of time with just their DCs together
SIL and BIL 2 are very very wealthy, they have 1 DS (11)
DH and I have 1 DS (8)
SIL/BIL 1 have 4 DC from 11-2
And although they're closer & spend more time together and have DS' the same age. Every summer for the past 4 years, SIL/BIL 2 have invited DS along on their summer holiday, he's been to exotic locations that he'd never get to go with us.
This year they're going to Cancun and at MIL's barbecue today, SIL 2 kept asking about DS , what he likes to eat? How strong a swimmer he is ? SIL 1 then kept interrupting with unneeded comments like how her DS whose also 11, is a very strong swimmer, won't get tired and has never flown out of the U.K., whereas my DS gets 2 holidays every summer.
We left feeling pretty awkward, I thought that was the end until I received a text from SIL 1 asking me not to be so selfish, and that we should share holidays away amongst all the DCs with SIL/BIL 2
I think that's bang out of order.