Most Helpful Guy
Tell him the truth.
Say, you value your friendship with him to much to be in a relationship with him right now OR you need some time to think if dating him is what you really want.
If he is your friend he will understand and be cool with it.
If he isn't cool with it, then he was using you
This is where you find out if he values your friendship with you, as much as you value it with him.
Trust me, if you stay with him, and he finds out later that you aren't happy, he will be mad or heartbroken.
Honesty and space are your best allies when it comes to dating or friendships.