Just tell them to stop touching
Someone loves me but I don't like him in that way. What do i do?
Let them down easy. At the least you will earn a reputation of being a jerk, and at the worst you'll end up liking them later on and be rejected by them!
Tell him you just wanna be friends.
Do what you feel is right. No one should force you into something and you will deeply regret it if you cave in just because you feel bad. That's life folks.