Not bisexual?

So I'm 21, and just got engaged to the love of my life who is a male. My whole life I've identified as bisexual, but I've never been intimate with a female. The thing is, I appreciate the female body and I definitely have a "type" when it comes to women, but I don't think I'm technically attracted to them. I had a girlfriend once in high school for a short while, but didn't feel inclined to be sexual with her beyond hugging, kissing, and feeling. She was BEAUTIFUL and I viewed her as my partner and I loved her and I could definitely see us getting married and raising children together, but sex really wasn't on my mind.

When it's come to all my relationships with men, I have a slightly higher sex drive and have much more easily been sexually intimate with them. And obviously I've had sex with my fiance.

I was recently told by a family member that in order to be bisexual or gay, I have to be sexually attracted to them. They weren't mean or anything and it was a pretty good discussion, but they insisted that technically I should be straight based on the definitions of sexual orientation. We ended up trying to figure out what my sexual orientation should technically be but couldn't really find a solid definition.

It's really not important or anything, especially since I've found the love of my life already, but I'm curious about what you all think.