Recently our 17-year-old daughter introduced her boyfriend to us over dinner. He came with another girl which we initially thought was a common friend. No, that was actually his other girlfriend. Super nice girl, very pretty. That dinner was awkward to say the least. My husband already doesn’t like him due to this whole poly thing. I just don’t understand how our daughter could be okay with this, no matter how good the guy may be.
First off, if you don’t want to be a shitty parent, it’s not your choice at all. Now, for a 17-year-old, I can’t really say that they truly understand what it means to be poly, but it sounds like you don’t either. The only thing not being supportive is going to accomplish is pushing your daughter away.
Best resource I’ve found for what it “means” to be poly, https://www.goodreads.com/book/show/52569124-polysecure
I say “means” because love is a spectrum and there’s no true definition.