How do I keep a frienship when the feelings are stronger on one side?

I have to quote out of book now.

It's from Empire Falls by Richard Russo.

"You can't love who you don't have feelings for. Don't ever apoligize for that."

As far as your best friend goes, if you can't love him, then that's fine, he should be grown up enough to understand that.

If he gets upset, and doesn't want to be your friend anymore, then let him go. It would be clear from that, that he never intended being your friend, but rather your significant other. Friends come into our lives, friends exit out of our lives. We can't change that.

It's all part of the growing process. Don't be afraid to grow, no matter what the sacrifices are.

I'm curious why your feelings never evolved beyond friendship for him? What impede it? Sounds like you have been honest with him and most importantly yourself. If he is truly your best friend then he will continue to be your best friend even when you want to date other people. Talk to him about it.