If he's the one you want to marry, date him, but I'd hold off on the sex. That way you'll know whether or not he really wants you or just your body. I'm a male, too, btw, so take this as an inside secret. And if you're still in the college aged years, I'd really think twice about all of it. You're not ready for marriage at that age.
Once you graduate, they'll always be another that you'll fall in love with. This would really have to be "The one" for you if you want to force your way out of a good friendship and into a relationship.
Never look at anything in the dating world within a one or two year window. It's where you see yourself 10, even 20 years down the line.
This doesn't sound as if it applies to your case, but we know it's true that today's young people continue to sleep with person after person throughout the college years. Than one day they get bored with that and they just basically "Pick one" to marry.
Those that refrain from pre marital sex have a 7% divorce rate in this country. Those that have slept with 5 or more people each have a 45% divorce rate. Those that have slept with 20 or more each have a 67% divorce rate.