Your son looks to you as a model in every area of his life. Have you ever considered whether or not you are modeling healthy sexuality for him?
I have spent countless hours counseling men whose fathers' sexual role-modeling was either absent or, worse still, destructive. The absent role model never discusses sexuality with his son. He doesn't know what to say about it, so he says nothing and hopes for the best.
This Christian role model has to be honest with other adult men about any lust issues in his life. He responsibly blocks the Internet, and he monitors TV and media intake for himself and his family. He is emotionally connected to his son enough so that they can talk about sex. This father is a good, general role model for male sexuality.