Sister in law rant

My sister in law is sort of snobbish I guess.. she was very rude when my husband and I decided to get married.. we’re young but he’s been able to support us. She pretty much told me that we would end up homeless.. she likes to point out that we make less than ideal income.. but anyways, her fiancé is apparently very wealthy. They’ve just set the date for their wedding and they’re having it in Cancun.. So, for the date she’s picked it would be $1600 round trip for my husband and I to go to Cancun and then the resort she has picked is $182 per person for each night.... we would have to pay a total of 3 nights.. Roughly, we would spend $2700 on the whole trip (give or take). That doesn’t even cover passport costs etc.. We’re expected to attend this wedding. Is it just me or is this a little outrageous?? I should also mention that I’m expecting my first baby in April and I just sort of feel like it’s inappropriate/dumb that we’re expected to spend this much money just to attend their wedding... My husband and I have decide not to attend the wedding but we’re waiting to tell because my sister in law will probably start a riot OR she’ll call us out for not being able to afford this... I just needed to vent a little bit because it’s frustrating and makes no sense to me..

EDIT..

I’m not at all saying she should change her plans. (Because Who wouldn’t love a wedding Cancun?) but just don’t expect people to be willing to pay that much... I think it’s the fact that we’re expected to spend that much that bothers me.