Not sure what to say

[UtaGoesRawr]

This is kinda a long story..

About two years ago, I dated this boy for six months. I was madly in love with him, but he didn't feel the same about me. It took me two years to accept this and move on. Last year, I moved to a new school. My locker was next to a boy that I became good friends with. He gave me his number and we started texting one another, but I always sort of knew he liked me. I asked him if he did after Valentine's day, and he said he did, so we started dating. Around March, I found out he liked me the whole year, which makes me feel guilty because I really feel nothing for him. I told him I loved him, but that feeling I had with my ex just isn't there. I know I need to tell him eventually, but I just don't know what to say. He keeps telling me how he wants to move forward in our relationship, but I can't build up enough courage to do what he wants to (to clear this up, I mean kissing and acting all lovey-dovey around school).

What should I say to him without jepordizing our friendship?