BlueRose
I'm sorry but your post reminded of that old expression, "Why pay for the cow when you can get the milk for free?" That basically, sums up the whole "friends with benefits" experience.
It's clear that from your post that you've fallen for him. Maybe in the beginning you thought that you would be able to remain detached but you've discovered what so many women before you have discovered---that's extremely difficult to do.
So...since he means more to you than a one-night stand (for example), then tell him that. Let him know that you want to be in a committed relationship and want a future with him. If he says "no", then tell him it's over. Stop letting yourself be used.
Next time, don't bother with anyone who wants a "friends with benefits" relationship. Hold out for someone who isn't afraid of committment.