@Easterbunnygettingready
Maybe the poor woman just want confirmation the op actually cares about her dc... Wouldn't most biological parents want to know their dc are valued at the other parents home? Wouldn't we be pd off thinking our dc had been replaced by a new baby?
I had a dc on my dss's birthday.. 2 days later we all went to a big shopping centre to let dss spend his birthday money. Bf a newborn in McDonald's wasn't my ideal trip out but it was important dss didn't feel shoved out.
Yes obviously the way to do that is be abusivr toward and harass another woman...

I think you are actually far more likely to breed the opposite outcome if you act this way toward your children's step mother, far more likely to build resentment than love. Completely counter productive.
The way I see this thread is basically....
OP is not responsible for her SC in the sense that she does not need to concern herself with their school holiday arrangements, it's for her husband and his ex. She is not responsible for rationing his annual leave and ensuring he has enough, that's for him to do, he is a grown up.
Her DH is unreasonable for not considering his existing children and discussing with his ex how school holidays would work. However I do agree with posters that whilst it's not exactly fair, it doesn't seem in the best interests of the children to have them placed in a holiday club or elsewhere by their father when their mother is literally at home. However annoyed at my ex I was, I would not feel comfortable leaving my kids to go off to a holiday club when I was available to care for them. I think it's odd that so many people have suggested that tbh. Doesn't make DH any less unreasonable but you can't literally force him to take the time off work so if it was the difference between a holiday club or forcing them on a frazzled, exhausted step mother, I'd much rather (and so would the kids let's be honest), that they be with me their Mum.
When posters say 'its not your problem', I don't see what is so unreasonable about that? If someone posted a thread as a mother saying that their children's step mother was trying to involve herself in the arrangements she was trying to make with her ex about the care of their children over the school holidays everyone would agree that she should back off, stop getting involved, nothing to do with her, between mum and dad etc... It really does seem on these threads that people are only ever shocked and appalled that someone would say 'not my problem' when it's something that benefits the parents, when it suits. I find that really annoying. There are so many occasions where parents would be really fucked off if a step parent tried to make it 'their problem'. You can't have it both ways.
To the poster who said there doesn't seem to be any step parents who like their DSC. I do. They are nice kids, we get along really well. I can say without a shadow of a doubt that I do not love them in the same way as my son. He is my entire world, they are part of my life, nice parts, but they aren't my life in the way my DC is. I don't miss them when they aren't here although I don't dislike them being here either. I'm completely middle ground I feel. I don't see what the problem with that is. I'm not responsible for my step children, they have two parents like all children who literally have responsibility for them. I am kind and welcoming and there have been times where I've done lots for them when their parents have needed a hand but I do not accept that it's my responsibility to do so simply because I'm married to their Dad.
I also think a good relationship with the ex is really important in making sure things work out well. Honestly I'd not be doing a single favour for a woman who sent me abusive messages when I'd just had a baby. Not a chance. And honestly the drama and stress it would cause having to deal with that probably would make me wish DSC weren't around. Of course someone who has to deal with an ex like that is going to think it would be easier if the kids weren't there!
There are bad step mother's and there are bad exes. And I do think some exes need to realise that the way they act can have a really detrimental effect on how someone else will view their children. We are all human, it's not the children's fault at all, but you are going to start resenting the fact that they bring such drama to your life if their mother acts like an idiot toward you.
I actually do think my DSCs mother can be a bit difficult with DH sometimes but I don't get involved in that. She has never said a bad word to me and that's what I'm personally bothered about. DHs and her co parenting relationship is theirs, he's a big boy and can stand up for himself, as long as she is not an arse to me then I'm quite happy. We actually get along really well and I can't explain how important that has been in building the relationship I have with the DSC.