It turns out, He already knew. As a teenage skate punk, he was convinced that my wife and I had pot hidden somewhere in the house, and he spent hours searching for it. He never found any. We quit smoking it before we became parents. What he did find was that dad had a little secret. Then there were the computers. He's always known more about them than me, from the get go. He became aware of the history features long before I did.
And I thought I was doing such a good job hiding my websites.
At any rate he is , to use his words "down with that". And I am feeling very relieved and liberated, and proud to have the son that I have, even though, as has just been demonstrated, it had a lot more to do with luck than parental competence.