Am I being helpful or up-ending the wedding?

I can't understand why you have not the parents before?.
You're only going to meet them on the wedding day? It's not married at first sight.
Seems very unusual to me.

Ah. I don't think this comes across in your original post, I understood that you'd gone ahead and invited people without discussing it with your daughter. I don't know if it's too late to amend it, I think you'd get a very different response. Your daughter is being ridiculous.

Why don't you know what to do, surely it's obvious?

She doesn't want it and as it's hers and her fiance's wedding, you respect that.

Makes perfect sense then as they are close by. I don't understand what her problem is. Maybe she just feels like she is missing out on it.

For what reason, though?

The hosting of guests the day after is like an extension of the wedding. Their wedding, not OP’s wedding. If people want this they usually organise it themselves as part of the wedding. Then there is the background fear of, is it everyone or only certain folk. Will people not invited know about it, and could it cause issues. The bride to be doesn’t want to think about such matters, they have lots else to think about and do.

The hosting of grooms family prior really means the bride and groom are obliged to attend. It would be odd and awkward if it was held but the bride and groom were not there. That means pretty much forcing them to fit in something else before the wedding that they are probably not up for, no time or no mental capacity. Plus, if they DID want this, they would have organised it themselves, so they may just not see it as necessary. There’s no mandate you have to be forced to meet everyone’s relatives prior if this has not as yet occurred organically over the course of the bride/grooms relationship. If this is the case, you simply exchange names and say ‘hi, nice to meet you’ at the wedding, hardly a crime.

When I got married (ages ago), my parents, in-laws and some close family went out for lunch the next day. I was adamant I didn’t want to go - I thought I should just be with my new husband and also would be tired etc. I do remember also feeling a bit offended that they’d want to gather again without me. Honestly, typing that now, I can see I was being totally unreasonable but that era of my life was a bit bridezilla, frankly.

In the end, the wedding was so fun that we wanted to go to the lunch on the day after, to enjoy everyone’s company some more and to debrief and relive the funny bits. Possibly she’s a bit the same. Just wanting to be in control.

I did, however, arrange for the 2 sets of parents to meet before the wedding and we were both there to help break the ice. I think she’s being a bit unreasonable in refusing that, but perhaps she’s just feeling busy and stressed.

Maybe they have something in mind for the day after themselves, but I would have thought meeting the parents beforehand wouldn't be an issue? Surely it's better than meeting them for the first time on the day, and it's not like the bride and groom have to be a part of that if they're busy.

Is there something they suspect you might clash on, and they don't want to risk any hoo ha or fall outs just before the wedding?

I think meeting the parents of the groom should be done before the wedding if possible although it does seem very last minute if they live close enough to attend.

The family event sounds normal too. Is it because she cannot attend? Is it because she maybe wants to monitor what you are saying to her future in laws?

Unless you are demanding she and her husband come it's absolutely nothing to do with her. You can host who you like in your own home. Both the events you describe are often hosted by the bride or grooms parents .
( I'd expect that she and her fiance may well wish to meet with their parents before the wedding anyway?)

Why would you bring it up to her again though? That does make you come across as pushy, she has already told you she’s busy and those events don’t work for her.

I don’t think you were wrong to offer and these are things that many weddings I’ve been involved in have had. Especially the gathering the day after for those who are still around.
The only thing I can think, is what the others have said, that it is very short notice and it’s just one too many things to have to think about. Her reaction seems overly emotional and a bit odd. A simple ‘well it’s a nice thought but I don’t think I can handle another event at this stage.’ Would have done.

I think both of those events seem great, but I don't think the B&G would necessarily be expected to attend.

It is a bit odd you've never met his parents. My parents are the most unsociable people on earth, but arranged to meet DH's parents as soon as we were engaged.

Seems perfectly reasonable on both fronts to me.
My parents only met my in-laws for a quick drink the day before our wedding like that, before we went for our rehearsal, so it could be time limited.

They then hosted a party the next day for everyone who had travelled from out of the area in my family and invited my in-laws to join in (they declined as they needed to travel back to their home). It was lovely as it meant we could catch up a bit more with people we don't see all that often, chat about how the wedding had gone. It meant there was less pressure to try and talk to absolutely everyone at the wedding itself.

I think it was a lovely offer. She's being over sensitive imo.

In my family, it’s very very usual for the family to meet the following day for an ‘open house’. We all turn up at whatever time, have a brunch or lunch and discuss and laugh about the previous days events. B&G will attend. It’s usually held at the Bride’s family’s house but I’ve also been to a ‘day after debrief’ at a pub local to the wedding. They’re great fun!

So no, YANBU.

I don't think there's anything wrong with offering, I especially think it might be nice to meet the grooms parents. I would say however after the wedding , based on experience, she may want the day after debrief with her friends as opposed to various family members. This has been fairly standard with regards to my group of friends.

You had the best intentions and she's probably just stressed.

Both very normal things to arrange and offer but maybe a little short notice, I’d assume she’s stressed out and approach her on that basis rather than looking for rights and wrongs in what you’ve asked her about.

Can you quote people when you're answering please.
Click on the Quote button which is under every post.

On the face of it it’s very weird for her to be so upset at your offering of this so it really depends on how you brought it up and how your behaviour is normally. Personally I wouldn’t want to do a last minute thing the day before my wedding with parents, nor the day after simply because I would already have plans or thoughts for this time.
If you just offered with no pressure and she got angry and upset she’s obviously being unreasonable, if you’re being push then you are.

Is there more to this than you've told us?

If you simply offered, why would she get very upset and tell you, you can do as you like?

It sounds to me as though she sees it as added pressure, but a simple 'No thank you mum' would be more fitting if there's nothing else to this?

My SIL had a buffet lunch the day after for close friends and family, but the bride & groom were not there - they had left for their honeymoon.

She hosted at her own home, but had it catered and it was lovely. A chance to catch up.

If that is the sort of thing you want to do, I am not sure it’s up to your daughter. If however you want to extend the wedding ‘event’ then it is very much the choice of the couple.

Totally normal to meet the other parents.