To not go to wedding party?

[FartSmeller]

We've been invited to BIL and SILs wedding party. They are eloping and having a party when they get back.
The relationship history with us isn't great, there's been a couple of fall outs between my DH and his brother and me and SIL went through a rocky patch. All seems to be getting back on track now though.

Anyway, the wedding party is on the same night that I have tickets to go to the theatre with my sister. I don't get much time alone with my sister and we have both really been looking forward to this.

Wibu to decline wedding invitation? We already missed the christening they had as we were on holiday and they didn't give us enough notice to change the date.

YANBU. It's not as actual wedding, if they wanted everyone there so badly they wouldn't be eloping. I'd prefer the theatre if it were me

*an not as

I would too, but am worried it will come across as a snub. Especially after our past tension and missing the christening.

If they were that bothered about you attending they'd have checked the date with you before deciding on it. Or given more notice

You already have plans, doesn't mean your DH can't go alone.
Tell them you will try and call in before or after with your sister if they don't mind her being there.

The christening is irrelevant. You were on holiday. No reasonable person would expect you to cancel your holiday to attend a christening.

I think you should honour your existing commitment to your sister. As PP have said, if they were that bothered they should have checked that the date worked for close family and friends before sending out invitations.

Thanks, it's good to hear an outside point of view. I've spoken to a couple of family members who think I am being a bit unreasonable over it.

Just be really nice about it and explain fully why you can't go, suggest you meet up separately for dinner or something, and send a really great wedding present. That way they will get the idea that it is just an unavoidable clash and not a snub - the nicer you are about it the less likely they are to think its a snub.

Could the theatre tickets be swapped to another night?

I think, however annoying it may be, I would go to the wedding party if you/DH are trying to patch up your relationship with them. If you don't go, they will inevitably be offended.
I don't actually believe you would be unreasonable to go to your prior commitment, I just don't think that is what I would choose to do myself.

send your DH alone?