That blocking us from his home internet only confirms our suspicion of his use of porn. And remind him by granting us access to his internet doesn't give us full access to his personal browsing history and that his secrets are still safe. Is slap down a $20 and say if it's not porn than you're just a cheap freak and this should cover our weekends use.
Sometimes to only way to defeat weirdos is to use their weirdness against them.