Sister in law drama

I'm sorry you are dealing with that. I know it's a lot when people have destination weddings the same year as yours. Can you just sit down with your fiance and come up with a hard savings plan for the next 7 months to make both happen?

I agree with MrsD. You're in an expensive stage of your life right now, but it's worth looking into your finances and seeing if you can come up with a savings plan to enable both to happen.

I think it's a little ridiculous that your in laws suggested moving your date. You set your first so her daughter had your date as a variable to take into consideration when setting her own.

Honestly if you knew she was having a destination wedding and you both still committed to the wedding there's nothing you can really do other than drop out and not attend. Trying to budget for your wedding and hers would be tough but that should have been a given in the beginning before committing

I think you can come up with some hard savings techniques to implement in the coming months, but if you really can't swing it, you're just going to have to tell SIL that you can't make it to the wedding. You can move your date if you really want to, but I definitely wouldn't. Stuff comes up in life, and brides and grooms need to understand that destination weddings usually shift a good amount of the financial burden onto their guests.

Side note: are you communicating directly with her? Why does it seem from your OP that you only talk through your fiancé's parents? I'm assuming SIL and her partner are adults, why would it fall to her parents to have to remind her of your wedding date?

WOW. Your future in-laws are jerks. You absolutely do not need to change your wedding date (are they going to refund the deposit? I highly doubt that), nor are you obligated to go to the other wedding. If you see no way of affording this DW, then you can't go. It's pretty simple. I personally don't care for DWs, so maybe I'm biased, but money is money. You have what you have, but by no means should you go broke over going to a wedding.

Most people understand that when they book a destination wedding, they will be alienating some of the people they invite. You all had conversations beforehand, however, and so she is likely assuming you were already saving for a DW and she may not realize what a burden it has now become for you.

Part of me thinks they had to have known it would be tight for you, but my bet is that
they purposefully chose to do it sooner because they felt that was
expected of them, i.e. We got engaged first so we have to get married first.

Having an open conversation with SIL and FIL's about it and just being honest that money is really tight might help later on in case you have to make the hard decision not to go. You are completely valid in being upset, as you booked your date first.