In-law blended family holiday drama.

Your SiL is keen to push this all through to make it legitimate and try and deflect from her poor behaviour. I would stick to my guns - it’s not all happy families and we’re not all being swept up into one big holiday.

What an unpleasant, mean and judgemental attitude. I am so glad you're not a member of my extended family.

All of the adults in this situation will have their own opinions and can voice and deal with them as necessary. However there is a young child who has already experienced being picked on and excluded who needs the protection of these adults to make sure that they are not exposing the poor child to more of this behaviour.

This

@w104ever the new partners children are suffering with their parents split and being flung into a situation not of their making.
There is bound to be a few issues. Perhaps this will be the opportunity to get to know the kids better. You can challenge any issues that may arise.

"Within two weeks of SiL telling her children that their parents' marriage was ending she introduced them to her new partner and his kids and they moved in with him less than a month later, so from the outside this has all felt a bit rushed to the rest of us"

It is an understatement to say that this is not somebody whose judgement I would trust.

She moved her new boy toy/boss within a month???

I would give this mess wide, wide berth.

"I can see her point in that it might be hard for his children if they knew their dad was going away on a holiday and they weren't invited."

I think they will be more upset by other aspects of his behaviour.

I don't see what difference it makes that her boyfriend is also her boss.
It's just that someone does not have the right to invite extra people on a fully paid for holiday. That's a ridiculous piss take.
It matters not whether he's her boss, her chartered accountant, Elon Musk or the dustman.

Obviously if he wants his kids to come he must pay for them. If that doesn't suit him then his invite is rescinded.

Pretty simple really.

It’s understandable (natural? Ironic pun…), that your MiL will be bowled over by new events, ‘new’ grandkids, and there’ll presumably be a feeling of betrayal re: your SiL’s recent ex, but…it’s not your (or her?) call to make. The ‘new’ kids won’t fit in till they’re a more regular part of the family and that involves…family events. I feel more sorry for the SiL new partner’s ex. Her kids off on a jaunt with her ex and his new family but…it’s the new dynamic. Some people have no grandchildren. Your MiL’s extended brood just got bigger.

She probably doesn't trust him enough to leave him alone.

Maybe tell your MIL quickly before you find the children’s places are booked and it can’t be changed 🤣

Agree and also that it’s probably not wise for their first holiday together to be with her entire family - but it doesn’t sound like common sense is your SIL or Boss Man’s strong suit 🤔

4?! Oh that’s even more sad 😢 I have a 4 year old and imagining his little heart if his dad chucked me out or vice versa and got a replacement is too sad.

I would send a message to MIL saying you don’t want to go if the kids come. They haven’t even had a holiday together just them yet!!! Once they do that and it’s all solidified a bit, it will be different. It’s too soon no matter what some other posters say. I say this having been a stepchild to 3 different step-parents.

Everyone is also assuming the step-kids even want to go, maybe they don’t want to go away with the woman who in their eyes kicked their mum out of the house and her strange (to them) family?!

I feel sorry for all the children in this situation, especially the sil’s. It must be so upsetting for them to have their parents split up and in a heartbeat have to be living with people they don’t know. Probably why one of them was being unkind. Acting out his feelings on the op’s kids. No winners in this unfortunately.

I must admit OP you are a better person than me as l could not stomach your SIL and new man behaviour,.absolutely disgusting when you mentioned kicking his own wife out of their home and instal SIL in it, SIL has no shame.

I genuinely think the holiday should be postponed. Your MIL is entitled to say she just wants to spend quality time with her own grandchildren and not include the children of a stranger. Postponing the holiday would give everyone a chance to get to know each other better. Or possibly show, over time, that a joint holiday simply would not work. I must say, given everything you have said about your SIL, I would never want to be in the same room with her ever again let alone away on holiday. I hope a suitable resolution can be found. I would definitely not want to go under the current circumstances. Good luck.

With your FiL, BiL and Hubby get together and say a firm no to SiL. Expect drama but don't let it ruin your time with MiL. You're a lovely daughter in law to have and your SiL sounds like a toxic person to be around. Stay strong and have a lovely holiday.

I know you have your concerns about your child but this really doesn't have a lot to do with you. I can't imagine just how hard this is for your PIL. I'd support them in the decision they make and wouldn't dream of influencing it.

What ages are all the children as the older ones may be bullying younger ones

I would encourage PILs to leave the holiday for a year to at least give everyone the opportunity to get to know each other better. You all going on holiday so soon will be a disaster. Plus in a years time it will test if the relationship is going to last and the kids will have had some time to get used to one another.

Especially if he's not paying?