Have you discussed your desire to have sex with him yet? Somehow I think you may be sitting back waiting for him to make the first move. Well, there's no law that says the first move can't come from you.
But communication is everything in any relationship. If you feel your relationship has progressed to the point where sex would enhance it, tell him so. Try sitting down over coffee, in a non-sexual environment, and simply ask him if he would entertain the idea of having sex with you. And if his answer is no, ask him why not. But don't accept answers like "I don't know" - those are cop-outs and he's not telling you what's really on his mind. Tell him you care deeply for him, and you need some additional intimacy to sustain and grow that. I guess it's possible he sees your relationship as one of "just friends" or "buddies" but unless that's all you want out of it, you need to have this conversation with him.
I don't know him, but if he's a late bloomer or came from a background where sex was frowned upon or considered dirty or bad, he could be worried that it is somehow wrong to want sex. Also, a guy's ego may prevent him from trying sex for the first time because he "may not do it right" or be afraid of making some kind of mistake.
This is a tough one, but heartfelt conversation is always a great place to start - talk to him! Reassure him that there is nothing to be afraid of, and you can take the lead and help him discover the thousand different pleasures that sex can bring, one step at a time.
If during your conversation you feel like he's getting overwhelmed by the idea, take it slower - perhaps agree to not have intercourse, but lying together naked cuddling or even just baring your breasts and allowing him to fondle them might get his mind on the subject.
If after some serious attempts like this he's still not budging, you may want to consider finding a partner that is more in tune with your needs and desires. Hope it doesn't come to that.