My parents don’t know my fiancé even exists because they don’t support polyamory. Do i bother inviting them to the commitment ceremony?

We’re planning our commitment ceremony for next summer, but my parents have never met my fiancé. We are in a non traditional relationship (polyamorous and long distance), and my parents support neither of those. They know I’m poly, but attribute it to my mental illness, even though both of my partners are perfectly fine and all of their partners are, too.

I asked my sister if I should eventually invite them to the ceremony, and she said no because they will flip out on me. It’s not a legally binding marriage; it’s purely symbolic. It makes absolutely no difference to me whether or not they come, but although I know the answer will be “no” and “don’t embarrass the family,” they might be hurt if I don’t invite them. The only other family I’d be inviting is my sister and future brother in law. My sister said she would be there.

do I bother!