Would you expect your spouse to say something?

Nope, wouldn’t expect anything different were A a stepfather. If others would that’s up to them, doesn’t change my opinion.

As a family unit they have established separate finances. If B thinks it would be nice for the kids then B needs to step up and pay for them.

I assumed A was male to start with , but if B was female people would be expecting her partner to make sure she and her kids got to go, Not asking grandparents I'm on the side of A there, but as a family unit surely A and B should work together for all kids to go, rather than B not go either, I know I would, regardless whether grandparents know the step children be nice for siblings to enjoy time together

And mine is that if B thought anything of A he’d respect the agreement they made, recognize the generosity of the grandparents who have paid for him and his joint children with OP, and not look to pass off the financial responsibility for his children onto anyone else 🤷🏻‍♀️

My view is that if A thinks anything of B and their children they would want them to be there on the holiday rather than go without not only their step children but B as well, (not to go to their parents expecting them to pay more I am on As side there) but at least help with cost towards their step children coming after all it would be nice for their children to have their siblings on holiday too

Seven years of completely separate finances. A ‘should’ not feel obliged to do any such thing.

After seven years A is a CF, he should be helping to ensure the family holiday goes ahead even if B pays the bulk.

Personally wouldn't expect anyone to pay for my child even my own parents, let alone my partners parents (not his child)

This is muddied a bit as you have joint children.
i was a step daughter and had step siblings. While we were and still are a close family, it was very much that grandparents stayed close to their biological grandchildren and did token things for step grandchildren. We never thought anything of it and never expected anything from step siblings grandparents.

Reading all of these I agree with A.

why would grandparents have to financially treat all kids the same. B’s kids aren’t their natural grandkids. It doesn’t mean they don’t like them or respect them, but this is what happens in blended families. They have their own grandparents, and not should A expect gifts etc from the grandparents of the ex-partner. Stuff is expensive, not everything can be funded. Also sounds like the grandparent sill treat their step-GC at Xmas etc.

I do think A & B should jointly fund B’s kids to go though, as A is a huge part of their lives and shouldn’t treat the child’s siblings outwardly all that differently. They’re a family unit. Grandparents are extended family so it’s different.

Separate finances aside you could still contribute towards step children coming. I think it’s fine that your parents don’t pay for them but either you pull together to pay for them and you all go or no one goes.
Its not much fun being the excluded step child (been there). I think you should make more of an effort.

I have 4 DDs, 2 with ex, 2 with DH. Mine were around 9 & 7 when DH came into their lives. They had little to do with DHs Dad (his mum had passed away), and really never felt the need to as they had their own grandparents. They exchanged pleasantries when they would meet, but that was about it. We never pushed for or fostered a grandparent/grandchild relationship either as we didn’t see the need. I absolutely do not think that spouse B should be making a big deal of this. They’re teens now, the boat has sailed. Besides, they probably have no interest in even going at this age. Expecting Spouse B’s parents to pay is unreasonable. I would leave B behind and go on my own with DCs.

This has been highlighted in the past when I've asked a few questions about what he's spent on DSC and his answer has been it's none of my business what he spends on them. Which is fine, but then I don't expect to contribute toward anything for them either in that case

Wow.

'None of my business'...... 'which is fine'......

Your post screams at me that yours is not a happy marriage.

If the current setup with defined separate finances works for you and your partner OP, that’s great. But he just shouldn’t try to change the goal posts now.

I think sadly you aren’t a family & don’t appear to act like a family unit. It’s them vs us, not us as a family. Sadly you should have chosen to become a family unit before bringing other children into the dynamics & the SC are going to feel like the outsiders

EDIT just to clarify this is coming from someone in a blended family unit with both SC & biological children. Both families accept that we all became one family when we decided to get together & then even more so when we brought another child into the family. There’s no them & us, no step vs biological, it’s just us as a family

I think this is really sad. My DC have a step-parent on their dad's side and his in-laws have always treated them exactly as if they were "real" grandchildren. Likewise when I was in my second marriage (now sadly over) my in-laws treated my children the same as the child of our marriage.

I can understand older people feeling differently about step-grandchildren but it is sad for the kids to be made to feel second best. If you have to pay for them to go on this holiday, I would be careful not to let them know who's paid for what.

Being part of her family and being her financial responsibility are distinct things. They aren’t shared children and they’re not a shared financial responsibility, and it appears they never have been.

He wasn’t forced to agree to this in the beginning, and OP isn’t obliged to start paying for his kids because it now suits him. If he wants his kids to go then he needs to pay.

A, you are being unreasonable. Your stepchildren are children of the family you and B have created. Your parents are being unreasonable, but it seems they have taken their lead from you. How can you have separate finances and share children? You’re a family, share your money and look after your children (all of them) together. You can’t compel your parents to act reasonably, so I would say “thanks, we’d love to come on holiday and will treat your offer as a contribution to ALL of our children going, and will pay the remaining balance ourselves”.

If you take your bio children only, leaving your partner and step kids at home, or refuse to pay jointly for your step kids to go, then you are being a terrible parent (to all of them) and partner.

@illingmeoftly do you see your stepchildren as part of your family? Not your extended family but your immediate family, you, your husband and your children? Do you see them as having a place in that family or do you see them as occasional visitors?

B should never of had a serious relationship with A if they were aware of the horrific way As family would treat their children.

Step children are children - they should be treated like any other shared child, not ostracised. The fact A allows their parents to treat their stepchildren says a lot about A and their attitude towards the step kids.

A needs to give their head a wobble and imagine how they'd feel if anyone treated their bio kids that way.

A is being entirely reasonable, as are A’s parents, B has very high expectations. Raising this to A’s parents is rude, hurtful, ungrateful and entitled.

HRTFT.

With A and grandparents all the way. B can pay for her/his children or don't go. I'm not grandparent yet, far from it, but I would never recognize my child's partner's children as my grandchildren, they'd be unrelated to me in any way. And I'd never pay for them.

The -step have their own parents, their own grandparents and they should pay for them.

As a step child and step mum I completely agree with this.

In this scenario if the other children would like to go on the holiday too we, as a couple, would pay for them to come along. Our finances are mostly joint. They may prefer to be with their mum that week?

My parents have always been a bit hit and miss with my (now grown up) step children, but we live a long way from the GPs so more understandable. It does get to me a bit sometimes, but you can’t force these things.

I think this was a ridiculous suggestion on the part of the grandparents but, that aside, I would think of it as a large contribution towards a group family holiday, rather than them paying for only some of the party to go. In that instance, I would expect both A and B to split the cost of the holiday for the step children.

He’s managed to understand it well enough for seven years.