To not want to go on a 'surprise' forced holiday with MIL and 3 Nephews

You have to be honest. Stop trying to keep everything on an even keel.
Sadly, your DH isn't going to tell his mother, so you may have to. Even if you only see these children once every Preston Guild, if you don't want to go, just tell you MIL that it is not something you and DH wish to spend your time doing.
If she throws a hissy fit ignore it

What ties? people you only even know because you happened to marry someone who is related to them?

why "must" people see other people's kids?

I too would suck it up for a few days a year. Maybe try and book a spa or something adults focused while you are there to give you a break. Is there anyone you trust who could take care of the dog for a few days if it doesn’t deal well with the environment?

If you are planning on having kids yourself weekends like that when you have more hands on deck to help will be a godsend, particularly when you are the ones with little kids.

For many people those closest to them are not extended family.

DH and I have a fantastic social circle who we spend time with it just doesn’t include extended family as we’ve never been close to them.

I would say sorry MiL but this type of break doesn’t work for us. The kids wind the dog up and instead of being a relaxing break, it becomes very stressful. Frankly, last time we couldn’t wait to get home. We love you all dearly but not to go away with.

Do you think you'll want anything to do with the children once they're adults? Is it worth investing a little in the relationship while they're young, so they can have some good memories with you? Could you leave the dog with a friend/sitter if it's not the environment for him/her? While the whole thing wouldn't have appealed that much to me, even once I had a child, it's often worth investing a bit of time for the sake of family cordiality - you might start to enjoy it if you go with an open mind.

It's pathetic to think that relationships should be founded on some parties in said relationships being forced/coerced into doing something they do not want or enjoy doing.

They've done five years of this. They don't enjoy it. They've given it a good go and it's not for them.

It's not just the time though is it? It's the expense of it which likely does or could take away from their ability to actually book and go on a trip they actually want to go on.

Nowhere does OP say that she or her DP doesn't like the kids-they just don't want to go on kiddie-centric holidays when they, themselves, don't have children. Believe it or not-other people's lives don't revolve around you and your children.

If you didn't have kids and weren't forced by virtue of having them-are you seriously saying you'd be happy to pay for the expense and give up your time to go on kiddie-centred holidays every single year?

If there's a potential fallout because OP and her DP want to do their own thing and no longer go on these holidays that they don't choose or have a say in-that is truly on the MIL, not the OP. It is not her responsibility to keep doing something she doesn't enjoy doing and actively dreads to spare someone's feelings.

You are responsible for your own feelings. No one else is responsible to cater to them.

It's not impossible to get out of, just say this no longer works for you. Life is too short to do things you don't want to do and to sacrifice your comfort for someone else.

Don't over explain, just say it doesn't work for you, thank you for the invite but I have to decline.

Unfortunately the dog has started snapping at random dcs. Such a shame but obviously he's stressed and can't be left.

I agree. Op,Your MIL loves getting her whole family together. In the future, looking back there will be .memories and 'Do you recall when...'
You could lighten up about the children and your MIL's arrangements -it's Christmas. Get one of the.children's new games out and play with them, give your MIL a.hand in the kitchen, ... sing Xmas carols. Join in and make your MIL's.day. You might even enjoy it all.

Nor me. My offspring, two families did center parcs a couple of times but they're bored with it now. This year they've done lodges and cottages on the Lleyn peninsula and Anglesey. Kids and dogs loved it

I don't know, it just seems a very individualistic and selfish way to approach life.

So does pushing a kid-centered holiday onto your childfree son and his wife instead of asking what they would like. There could be at least some type of alternation.

Posters often moan on here about how everything shouldn’t be child-centered yet OP is seemingly selfish not to want to go to a child-centered holiday place for the sixth year in a row that she and her DH are only going as to not hurt feelings.

The amount of emotional manipulation on this thread is staggering as well as the transactional nature. Some posters telling OP maybe when you have children, these children may watch them, or likely maybe they won’t and will be doing their own thing or OP and her DH may not have children at all. Once most kids get to teenagers, they aren’t going to be jumping at the chance to babysit younger children when they can be hanging out with their mates unless there is some money involved.

I have a lot of aunts and uncles. I saw some a handful of times a year and some several times a week growing up. My relationship with all of them is pretty even. I can’t even say I have a favourite nor were any of them the type to get down and play. I only knew what they were able to give in the ways of attention and it never came to mind they should be doing xyz because they are my parents’ siblings. I do know that xyz aunt or uncle taught me this, made the best dessert, always teased me in a kind way, gives the best advice, the most knowledgable about xyz, etc.

OP and her DH see their nephews when they can and do show some interest and they may find visits better once the kids are older and less rambunctious. Opting out of a holiday when they see the kids several times a year is not going to scar their nephews..

There is no way that I’d go to this.

Come up with an alternative. I'm sure there are others in the group who would like a change.

Can you just visit for the day? (and spend the night elsewhere if necessary). If it's distressing for the dog you have the perfect excuse not to stay longer. Maybe your MiL thinks (wrongly) that you would be put out if you were not invited.

As long as you are fair you aren’t responsible for their emotional response

saying in advance ‘we love + value you but big family Center parcs weekends just aren’t our thing. Please don’t factor us in this year’

then ‘big group holidays aren’t relaxing for us, we won’t be coming’ on repeat every time

is fair, and polite. They might be upset. But if they don’t recover from it that’s a them problem.

Successful marriages require give and take. Go every other year and let your DH go alone every other year.

I can understand you not wishing to join your family for this particular type of holiday if it's not your thing. I have to admit though I find it really sad it's because there are children involved. I hope they never find out they are the biggest reason you don't want to join them. I assume they will always be in your life so how often can you refuse to be in their company OP.

You need to grow a backbone and just say you're not coming this year. I'd say I want to spend it at home as it's been a hectic year, or book somewhere else just the 2 of you + the dog.it won't get better til you say no.

I wouldn’t allow the nephews to wind my dog up.
If I went again, which I probably wouldn’t, I would make sure the children learnt how to behave with an animal.
If the boys can’t/won’t do as they are told, I would take the dog home anyway.

I'm genuinely shocked at how the language of "asserting boundaries" and "not being a people pleaser" is being used as a justification to wriggle out of basically anything that is even slightly inconvenient.

OP, this is your DPs closest family, and by extension, your family. An annual tradition that brings a family together is something to be cherished.

What a fucking depressing world this is, if we cannot once a year manage to look past the superficial annoyances and frustrations of those closest to us and value the ties the bond us together.

If you choose to be a parent you are choosing that some day you may be a grandparent
If you are child free by choice you have absolutely no control over whether your sibling chooses to have a child or not. So i dont think someone who is CF should be harangued into child centric holidays.

‘We’re not great with group holidays at the moment with sleep issues and the dog, but tell us when you’ve booked and we’ll come for a day trip if we can.’

would it have been different if they were your nieces and nephews and your mum booking thee holidays?