Ah this is still going, I was worried I would be bored today!
Can we all just keep a bit of perspective. She's talking about one night. ONE NIGHT! When she's just given birth to her first baby! She's not talking about selling her DSS on eBay or locking him in a basement for the weekend. Is there really so little empathy on a site called MUMSnet for a first time mum about to give birth, via induction no less??
We have made many adjustments to our contact over the years - to accommodate changes in job and holidays (for both DSD's mum and my DP), family weddings, illness (DSD), DSD's mum having a minor operation, snow preventing travel, school friends party etc etc etc. And my DP doesn't even have a particularly good relationship with his ex! But they both recognise that life happens and SOMETIMES changes need to be made.
@Boysandbuses I agree that a blended family has some extra considerations. I have one. But it's not as dramatic as you are making out. And to be honest, if my DSD really was as drastically affected by ONE NIGHT as you claim stepchildren will be, then I would be more worried about overall attachment with her dad if that's all it takes to make her question her place in the family.
Our DSD was looked after by family while I was in hospital on a contact weekend with a horrendous, drawn out labour. She didn't meet DS until he was 4 days old. She adores her baby brother and it has had zero impact on her relationship with her dad and me.