To be upset that DP doesn't want to come on family trip

Same. I despise caravan park holidays, we went on loads as a family for years and now my answer is a flat out no thank you. Not even if someone else is paying.

YANBU to be feeling upset. I’m guessing he hasn’t exactly been champing at the bit to think of holiday ideas for you as a family even if he doesn’t personally fancy a Haven in March. It’s obvious you want to go on this trip (even if it’s not other posters’ cup of tea and some are being quite sneery about it) and sometimes being a parent and a good partner means doing things to support your partner’s family connections. He has a family now and sometimes being a grown up parent involves recognising than his time might not be all his to freely choose how to spend it in the same way as when he was single or had no kids. I’m also guessing that you’re probably on maternity leave / looking after the baby most of the time and would fancy a break with the chance to have some others around you to help with the baby. I too would be upset if my husband wasn’t prepared to put himself out a little bit so that I could do something important to me.

I think I'd volunteer to work more if my husband told me I was expected to go to caravans at Haven with his entire family.

Not everyone likes these big gatherings.

This seems like a great use of your maternity leave, but it would be a terrible waste of his annual leave/the limited favours he can call in to switch shifts.

My DP comes from a big family (his mum is one of 7) and they are all lovely people, I enjoy an afternoon BBQ but I really couldn't cope with a haven caravan holiday. Given the weather in march it's likely you will be stuck in a caravan a lot of the time, I would find it claustrophobic.

Maybe he doesn’t want to use up favours at work to go on an extremely last minute caravan trip in the UK in March, which is really just an extended family reunion for you.

Haven?
Huge extended family?
Caravan?
March?

That would be a hard no from me

Just go with your DD and have a lovely time with your family. Let your DH save his annual leave to do something just the three of you. Win win.

I would hate that with my in laws and would try to get out of it, but mainly because they are very controlling and would want to create an itinerary for me and my family

YABU you wouldn't catch me at Havens ever. I don't blame your dp for not going. No-one books anything for me and expects me to turn up, unless it's somewhere lovely and 5 star.

Sometimes you have to suck it up, accept he doesn’t want to go, and go and have a great time with your family.

Her ‘first’ time away is a red herring - it doesn’t matter - she won’t remember:

Id love to see my family all together for a weekend away. Go and enjoy the time.

Whenever anyone posts about being asked to go on a holiday with loads of their DH’s family and doesn’t want to go, people always tell her to let him go on his own. Same applies here. Don’t make him have a holiday with load of your family. Just because he likes and gets on all right with them, that doesn’t mean he’s obliged to be keen on going away with them all en masse.

But does he know that? Who's sharing with who in the caravans? Also as family have booked it they have control over booking any activities you want to do e.g. swimming etc as you need the booking reference to book it (note that for haven you book swimming 4 weeks in advance, any other activities 12 weeks in advance). This means that you can't necessarily make an excuse of saying we have got this booked ,we will see you later. Maybe he feels worried you will all be expected to meet up each day and spend the whole day together.
Maybe he also would have liked what I assume to be your first family holiday one with just you and the baby.

You say he's unable to get annual leave. If that's the case then so be it.

Well come on then you can’t think he is being unreasonable. I love my in-laws but if they booked a holiday, didn’t tell me they were doing it and expected me to take annual leave then I would be avoiding it too. Very presumptuous of them

There's no way on this planet I would go on holiday with DH's family.

YABU. Especially as it was all booked without him being asked.

Then maybe he doesn’t want to use up “favours” last minute at work. There’s only so many times you can ask for last min shift changes before people get narked with you.

I wouldn't want to go on a caravan holiday in the UK in March with a baby and the in laws....

It sounds a bit unreasonable but then...they booked it all without speaking to you all first so, they are more unreasonable.

If it’s a last minute thing YABU. It can be really awkward to have to arrange things like that at work because it is an imposition on other people. The in laws booking a last minute caravan at haven in winter doesn’t seem like a good reason for him to do that.

Does he like going to haven sites? Many people loathe that type of place, or look down on them.

Oh, then yes I’d be miffed. Did you ask him about it before you booked it?

He gets to say no for himself, he doesn't get to stop you going or make it awkward for you to go. So seems fair even if not what you ideally wanted. Do you go to lots of his family events?