How do I let him down nicely?

Ok so I went on 5 dates with this guy...I think he is a great guy and he takes me on such nice dates. I always have a great time when I'm with him, but I really don't think that I'm that attracted to him plus when we kiss I'm not feeling the spark. I know that he really likes because he told me and my friend. How do i let him down in a nice way? I want to tell him something like "i think that you're a great guy and but I see u more as a friend...I want u in my life as a friend..." what else should I say? help help! i know that hes going to be hurt when i tell him, but what can i do?? i can't force myself to like him