How do I let him down easily?

Daniel

So I'm 16 and had sex with a guy with the expectation that it would essentially be a one night stand. The thing is, he didnt tell me he was a virgin until it was over. Now I know I should have asked him first because he's getting really attatched when I just want to keep my distance. It's at the point now where he's trying to say he loves me over text and I keep pretending I just didnt see that part. How do I let him down and tell him it was a one-time thing without hurting him? He's a great person but I just don't want a relationship or whatever "thing" he thinks we have.