SO with low sex drive?

I hear about women with lower drives. But my whole life everybody went on and on about what horndog dogs men were. Women and men both made it seem that way. But I got into my first real relationship last year, his drive never seemed as high as I expected from all I had heard but I didn't really consider it a bad thing... little over 5 months into our relationship we started having sex. Well once actual sex was involved I have came to realize this guy has like no drive hardly. He can barely go even once a day, meanwhile I am the horndog of the two lol! I really like this guy, aside from our drives being totally different we seem really good together (it'll be a year in a couple weeks). But I have to ask, why do you think his drive could be so low? I really expected different from a guy, and one that's never been with anybody else before at that. I could maybe see if we were older and had been with others? But he's only 18 (almost 19)? Thoughts?