To not attend a wedding I've already said I'm attending?

[Yvetteballs]

Reasons I should go:

I've already sent rsvp for myself and my daughter
It will make things easier for MIL
I have a dress
It will be pleasant and I don't minspd chatting away to people I don't know.

Reasons to cancel:

Already annoyed that I got a save the date card for the wedding then only got an evening invite. I don't mind an evening invite but the std card was misleading and led me to buy a dress I didn't need, too far in advance to return it.
I originally agreed to go because if I hadn't, MIL wouldn't have gone alone, which would have upset wedding family.
I'm only invited because I'm the partner of a family member who actually can't go himself due to ill health.
MIL is invited to the full thing. She's persuaded me to also attend the service and pay for my own meal at the wedding breakfast. I'd have to pay more for the wedding catering food than I'd have to pay for the pub lunch but can't have the normal pub lunch as I'm seated with the wedding party.
DD is very very quiet and will struggle all day.
MIL is putting pressure on me to get ill dp to go so that she won't be embarrassed that he's not there.bshe thinks I'm not making enough effort to get him to go.

So, the MIL pressure is the last straw. It's not me they want there, it's dp who can't go. I'm thinking of politely cancelling, maybe referring to DD's shyness/social anxiety and acting as MIL' S chauffeur. I'd need to drive her there, 1.5 hours and pick her up the next day. Will I be wrong to do this?

Pull out. The whole paying for your own meal and sitting with everyone else (if I've understood that correctly?) is very cringeworthy. But... do it soon before they make the seating plan etc.

I'd cancel asap. It's madness!

Blimey I wouldn't have let it get as far as this. As soon as an evening invite came through for a wedding that wasn't local, that would have been it for me. Can't your MIL make other transport arrangements? Doing a long round trip for something you aren't even attending is daft plus it will look suspicious because you are pulling out for a 'reason'.

I wouldn't go, they don't even want you there.

Do people really send STD cards to evening guests?

Really wish people would stop calling them std cards :o
I always imagine they open with "were you intimate with xxx between October 2009 and match 2010? Call the number below and STOP SCRATCHING"

Your mil is a grown woman. If she doesn't want to go alone she doesn't have to. You certainly shouldn't go to the wedding breakfast and service which you weren't invited to. I would think you were very strange and a bit rude if I were the bride (sorry).

Nop! Do not feel guilty!! Reads like your MIL is treating you like an old school 'lady's companion' you get to ferry her there, not actually be part of the meal and ferry her home after! If it's DH side of the family, is there REALLY no one she can travel with?

re: the wedding breakfast, errorofjusdgement, I think we're sitting part from the guests but in the same sitting timewise.

MIL is early 80s so I would like to help her out even if I don't end up attending myself.

Not 'sitting part' sorry 'sitting apart.'

Oh, god. Just say no. Feel.no guilt. Sounds like an (expensive) nightmare for you and your daughter. Who the hell does your mother in law think she is?? She'll know loads of people but wants you there all day with her?! Forget that. Save your dress for another occasion. Sounds like a shitshow. And that was downright rude sending you a std card but making you pay for your own dinner! Fucking ridiculous.