To not invite them to the wedding?

Are you having a sit down meal? Could you switch to spend your budget on a buffet? Think most people would prefer that anyway. You’re lucky to have such a close family.

In your situation I would say forget about the plus 1 concept. It doesn't exist in your wedding universe.
You only invite people who you want to be there.

cousin 1 has been with her partner for 5 years, they have a house and a child together and we have been out with both of them numerous times and have a friendship with him.
cousin 2 has been with her partner for a few years, and I’ve seen him once or twice but never really spoken to him.

You want to invite cousin 1 and cousin 1s partner because you know and like them both as individuals

You want to invite cousin 2. But you don't want to invite their partner because you don't know them from Adam.

Furthermore the point of a plus 1 is so that the guest feels comfortable because they will know someone at the event. Cousin 2 has their whole family at your wedding so will feel comfortable enough without their partner. Equally they are free to decline your invite if it's an issue for them

If you MIL wants an opinion on this, she needs to pay the costs of all the plus ones.

This is sensible and good advice👏🏻

I don't think you can invite one half of a couple. If you have a restricted budget I’d hire the village hall and do a buffet. Either that or restrict to immediate family only.

Could you only invite partners that you've met?

How many would this cut down?

Obviously leave out new girlfriends but if one cousin has been with their dp years you invite them even if you don't socialise with them.
Agree with others just have immediate family if cost is an an issue.

You're giving a lot of power to your MIL here. Is she paying? It's your wedding. If you have an aunty you're very close to of course she should come, if your fiancée doesn't he doesn't have to invite aunts and uncles but may want his close cousin instead. Do what works for you and enjoy!

How much would you lose if you cancelled and booked a bigger venue? It sounds like this one is too small and too expensive maybe.

Think about all the people you're cutting out.... would you expect an invite to their wedding? If you were invited would you want to go or would it feel like an obligation?
What you don't want to end up with is a load of people who are there out of obligation.

In my opinion, it’s terrible etiquette and hosting to only invite one half of a couple – they are a social unit. It’s better to discard some couples entirely in favour of the allowing all the plus ones necessary. Your budget is your budget – not an excuse to be a poor host, so if these people are really important to you, it’s even better to downgrade or cut out all the bells and whistles like expensive dresses, shoes, suits, flowers, invites, decorations, popcorn van etc in order to afford them.

The only exception is a group of work colleagues of whom you’ve never met their spouses.

Your fiance has a large family with 6 siblings. You are going to have to be ruthless if you intend to stick to a 50 person wedding. You should be able to invite your auntie who you are close to. This doesn't automatically mean he has to invite all of his aunties - he already has a bigger family.

You have to decide what your budget limit is and then prioritise accordingly.
If you want to be able to extend the guest list you will have to reduce costs elsewhere - cheaper venue, meal, entertainment, dress, drinks package, honeymoon.
Or have a very small day ceremony and a big party in the evening.
Or elope.

Drop the cousins! Or just invite them for the evening. I have 13 cousins and we do not get invited to each others weddings any more. I fully understand this as there is so many of us.

If you have particular relatives that you are close to - your auntie and his cousin - then invite them. It would be worse to hurt those two people by not inviting them than to offend others who don't make the cut even though they are in the same familial category.

So that’s what you go with, it’s yours and his wedding no one else’s.

Invite your list of 50. MIL picks up the tab for anyone she thinks should be there but isn't on the list? She might be less enthusiastic if her hand has to go in her pocket

Not inviting cousins is perfectly normal. I'd be really strict. At my wedding all my husband's six cousins came and we have never been invited back to any of their weddings so I'm a bit annoyed we asked them. It was my MIL who made us. We didn't particularly want to. If I would do it again 20 years later I'd strip the guest list right down and save the cash for the honeymoon!

And yes..no partners. Or just the ones you know well.No one can really object who you invite or don't invite realistically. No one really cares so I wouldn't lose sleep over it. Weddings are far too stressful anyway and you end up worrying about minor things like inviting partners of cousins rather than enjoying the run up to your day.

And another edit...if your MIL wants particular guests invited like all partners, she pays. Perfectly reasonable.

I personally agree that if you don’t invite the partner then don’t invite the person. I had this approach with my wedding. However, it’s different if you have a friend at work you want to invite who happens to be married vs a family member who has a partner.

I also think you could do it by engagement / marriage / children - ie if just boyfriend and girlfriend, no invite.

It sounds a total headache. Tell mil if she wants those extra folk invited then she can pay for them. But the point is I don't think you can invite People without their partners. Sounds like you simply can't afford this wedding. Maybe you need to reconsider.

It’s that fact that one cousin will get to spend the day with her partner whilst her sister doesn’t.

Are you sure cousin 1 won’t actually be a bit annoyed with you and it might ruin the friendship you have. Like I said in a PP- I’d be gutted if my SIL wasn’t invited and to be honest it would make me view you in a different way.

This is your wedding, not MiL's.
Your partner has more immediate family. No reason to not invite the auntie you are close to & her husband.
You add up parents, grandparents, siblings & partners, best man, groomsman & their partners. Any spaces left you both choose. Then add on cousins you like & friends for the evening.

We had very little money and had just bought a house when we were planning to get married. My MiL started with the "you have to invite" and was including her old neighbours 🙄. And DH had a far bigger family than me. We were paying for everything wiith no help. Realised we just couldn't afford it before we put down deposits. We eloped.

You can never please everyone. Do what makes you both happy and won't bankrupt you.
Congratulations, & all the best for the future.

Honestly op, anyone you haven't spoken to in two years or who you don't have a phone number for should not be invited. This is your day....to celebrate your love with people who care and love you. Do you really want to look back at your group photo and wonder why it's full of people you never see?!

Also accept MIL financial assistance to pay for an extra ten people.

I think that's a good idea. Could you book a bigger, cheaper venue? Don't bother with an evening do, just invite those you care about to your wedding.

I agree. To be honest I agree with your future MIL that you either invite partners or you don’t.

And to be honest if I were cousin 1 I’d feel so awkward if my partner was invited and my own sister’s partner wasn’t.

I’m sort of imagining this scenario for myself- i have a cousin who I see loads and he knows my DH. My brother and SIL ( who I see loads and am really close to) don’t see him anywhere near as much. I’d still be gutted if my lovely SIL wasn’t invited to his wedding - I’d feel so bad and it would ruin the day. I’d actually prefer for just my DB and me to be invited rather than me and DH but only DB.

to be honest you should have firmed up the potential guest list before choosing your package/wedding format.

I agree with your mil, it's not nice inviting one partner of a cousin and not her sisters, would probably bring unnecessary drama to your day.
In your post, you've mentioned an extra 3 people, can you just not accommodate them to meet in the middle?

It's absolutely none of MILs business.

But by picking and choosing which partners to invite, you are obviously going to cause upset. It sounds like you've booked a venue that you can't afford tbh.

Who is paying for this wedding? How much is it costing?