I’ve a big family too!
Not quite as big as yours but big enough, 5 aunties 3 uncles then add in their partners/spouses doubles that to 16 people, then 12 cousins and at the time I married half of them had partners/spouses and children...
Then ex is youngest of 4 himself, I’m eldest of 3 so 5 siblings + spouses/partners and on his side 5 nieces/nephews at the time although his parents each only 1 of 2 dc each side so not loads of extended family and one uncle was very unwell and being cared for by his wife and was unable to make it anyway.
You have to draw a line somewhere because no venue and no budget or organisation can accommodate unlimited numbers - hell even the royals don’t invite EVERYONE!
We chose to stick to aunts & uncles, their partners IF they’d been together a long time no new ones (we ruled out people who’d been around less than 2 years), spouses ok, cousins but again only cousins partners if they’d been together a good while/it was a committed relationship not just boyfriend/girlfriend (a couple kicked off about this and right enough by the time the wedding was happening they’d split up anyway!)
We invited all dc though which I know is unusual for mn but I was raised weddings were a family occasion and kids were included, plus I love kids and all the kids that came I knew well and wanted them there, they all behaved very well. We did have the benefit of not properly having to include them in catering costs though as it was a “village hall” type wedding and we had a sort of buffet type set up so it was approximate rather than exact numbers and about half the dc were under 2 and not really having a “plate” themselves but picking off parents meals and/or fed by what parents brought as things they knew dc would eat at that point in their development, iirc at least 3 were still bf too.
But there were daft wobbles and pressure from unexpected quarters but we held firm.
Eg i refused to entertain long lost relatives my mother thought “should” be there as they had been close to my grandfathers who had both passed by the time I married - I’d never even met them! Then fiancé refused to entertain inviting his mothers next door neighbour because his fathers a grump at such events and his mother wanted someone to dance with! Very out of character for both mothers to be awkward too - we’d expected even girded ourselves for the fathers playing up on something as they tend to be the bossy ones but they were actually really supportive and talked their wives out of their nonsense.
Weddings do weird things to people.
I also (way after I married) ended up working in the industry myself for a time.
You’re never gonna please everyone that’s impossible especially with a big wedding so you do need to draw a line.
It does make life easier for you if it’s something you can clearly argue applies to all, so tiered invites eg aunts & uncles but not cousins or even cousins but not aunts & uncles. Or no partners only spouses (bit old fashioned but is easy to explain)
Eg many of my cousins have opted to invite aunts & uncles with long term (the ones that are basically so well known/close as to be referred to as aunt/uncle themselves) partners/spouses included but not the cousins - totally understandable now our family is even bigger (now that all the cousins at least have partners and all have at least 1 dc) and the cost of weddings has gone up - it’s getting harder to arrange “village hall” type set ups, not impossible but harder.
A few of the cousins “eloped” - did the small overseas, immediate family only weddings which is also absolutely fine as an option. Rest of the family still sent cards & gifts and many congratulations and enjoyed the photos posted on sm.
Ex and I are both also army brats so had a fair number of genuinely good, close friends we wanted to invite (friends tend to become like family when you’re not living close to family AND have a shared experience in how your life works)
200+ we had!
We could have had much fewer but it really wouldn’t have been “us” at all, we did it on a budget inc quite a few guests contributed in the way of skills and other help and that was their gift to us which we were very grateful for, it was very basic in some ways and yet it was a great day that even though we’ve since divorced I still have people saying how fun it was. Even some stuff that went wrong simply added to it.
It sounds like it’s one particular person troublemaking - is there anyone in the family known to be good at getting them to wind their neck in?
We have a similar dynamic in part of my family but there’s someone in the family who is good at calming them down and getting them to see sense.
“but a huge row will come a close second!” Omg yes! Unfortunately true.
“You tend to move on from the friends that you invite to your wedding as life moves on” not true for everyone, I’m still friends with the friends I had at my wedding over 20 years ago, I’ve lost touch with 2 of them who emigrated pre sm and addresses got lost etc (keep meaning to look them up) but the rest I’m still close to.
If there are people not invited likely to show up yes the venue needs to be informed.
Someone I think really needs to tackle the main troublemaker on a 1-1 basis