Saying No Without Hurting His Feelings?

You can't hold your thoughts just because you're afraid of how he will react.
First off, he's responsible to how he reacts as long as you communicate in a reasonable manner.
Second off, if he's a loving and understanding man. Or a good boyfriend in other words, he should understand your point of view, and not force his feelings over yours, that's selfish.

i also believe you're being manipulated into giving him bj's. I doubt he's that hurt. And if he is, he's still manipulating you.