AITA for refusing to let my fiancé’s sister’s kids attend our wedding unless they pay a “child fee”?

Okay, Reddit, I need to know if I’m the villain here because my entire family is blowing up my phone. So, my (28F) fiancé (30M) and I are getting married in three months. We’ve been planning this destination wedding in Bali for over a year, and it’s costing us a FORTUNE. Like, we’re talking $75k minimum. To offset costs, we decided to have a child-free wedding—except for my fiancé’s sister’s kids because she’s a single mom and “family.”

Here’s where things get messy. My fiancé’s sister (35F) has SIX KIDS. Yes, SIX. All under 10. She’s always broke because she keeps popping out babies with deadbeat guys, but that’s not my problem, right? Anyway, I told her the kids could come IF she pays a “child fee” of $200 per kid to cover their meals, cleanup, and “inconvenience costs” (kids are messy and loud, and I don’t want them ruining my photos).

She FLIPPED. OUT. Called me a classist monster and said she can’t afford $1,200 on top of flying six kids to Bali. I told her, “Maybe you should’ve thought about that before having six kids you can’t afford?” She started crying and called my fiancé, who’s now begging me to drop the fee “for family.” But I stood my ground—my wedding, my rules!

Now the whole family is attacking me. My future MIL said she’ll boycott the wedding, and even my fiancé is “reconsidering things.” But here’s the kicker: the sister just posted a GoFundMe titled “Help My Kids Attend Their Uncle’s Snob Wedding,” and it’s gone viral. People are donating THOUSANDS, and she’s using the money to take her kids to Disneyland instead “to make happier memories.”

I’m furious! She’s weaponizing my wedding drama for clout and cash. I demanded she donate the money to our wedding fund since it was meant for our event, but she told me to “get bent.” AITA for wanting her to pay her fair share? Or is my fiancé’s family just jealous of my success?