Opposites.
He grew up in a city, a bad one at that. Taught him to kind of act like a tool. (Some people he knows from his childhood tell me he was a jerk when he was younger.) He's talkative and more social but never opens up. He was the kind of kid in high school that I would have hated, late all the time, went out a lot, teases like everyone he knew, flirty. He enjoyed partying and drinking and "getting effed up." He has liked a lot of girls. He has a huge family and extended family that he is weirdly close with. All the people in his life seem oddly touchy. He doesn't recognize some boundaries. He seems to only make friends with people that are attractive. (He stupidly told me which ones are attractive or cute or pretty.) He gets organic chemistry.
The main bulk in our differences is how we grew up. He has changed a lot (not a jerk anymore, tool behavior doesn't happen that often anymore, he stopped partying and drinking so much.) So he is a changed man, but these differences do cause problems from time to time since I will see something and wrong and he won't get it.
I on the other hand grew up in a small town. Have a small immediate family I am close to. Was the nerd in high school with no social life. Didn't date or have many interests in guys in high school. I have always been picky with my standards for men. Didn't drink until the end of my first year of college. I'm considered very inoccent. I don't talk much but I'm very open about my emotions and feelings. I'm fine with just having and only talking to a few close friends. And I'm not attracted to any of them. Nobody in my life is touchy and I'm not touchy with them. I see way more boundaries then he does. I don't get organic chemistry but I get physical chemistry and math.
We are very different socially and with our ideas of how a relationship should be and how we grew up and how we are with the people in our lives. He tries very hard for me, and I have expressed concern that we might be too different but he likes me how I am and he has changed a lot.