So, I'm the worst fiancee ever..

I've been telling my fiance for an eternity that I wanted a very specific engagment ring. In my defense, it wasn't extravagant. It's under $500 and absolutely gorgeous.
Christmas morning, he handed me a tiny box to open and voila! Ring! Which is fantastic and honestly, I'm so happy, but its not MY ring. It's not even remotely similar and not my style. I mean, its nice, but my heart was kind of set.
Help? I feel like a total jerk. I haven't said anything to him. I don't want to hurt his feelings, because he was so proud he picked it out himself.