My boyfriend asked me to pay for his sister's wedding and I'm confused

So my boyfriend of 3 years just hit me with something that left me speechless. He said since I'm making good money as a content creator, I should contribute 500k for his sister's wedding. 500K! In this economy where data subscription alone is a whole salary.

I laughed at first thinking he was joking. He wasn't. He said it's what family does, and that I should see it as an investment in our future. But we're not even married yet and I'm still paying my own rent and sending money to my grandmother in the village every month.

I love him but this one is giving red flag. Am I being selfish or is this actually crazy?