To cancel going to friends wedding

[Watdidusay]

We have a close friends wedding to attend in 6 weeks. It's been booked about 6 months in advance. We've prepaid for travel, hotels, childminding and bought traditional clothing for the event. I'm in the wedding party.

Just received an invite to my SILs wedding today (DHs sister) for the same date. In 6 weeks time.
Different part of the country.

Family are all saying we have to cancel the other wedding. We are going to be out hundreds of £.

AIBU to go to family wedding instead just to make my life easier? Everyone is angry at me for even considering not going to DHs sisters wedding. I feel terrible.

People can change their minds. Especially when they realise their parents are controlling arseholes with no respect for them. Tends to make decisions like this easier.

Never heard anything as ridiculous in my life. Of course you have to go to the original planned wedding. You are part of the wedding party FFS. Expect to never hear from your friend again if you pull out now

You must go to your friend's. It was the first invitation, plus you've paid for everything, plus you're in the wedding party.
Your DH's family should say 'Pity, but we quite understand.' That's the only gracious response. They are ill-mannered and trying to emotionally manipulate you. Six weeks' notice isn't realistic. Let them be angry.
Your DH needs to stand up to his family too.