Express your concern for him and explain your opinions of these materials that contain portrayals of sex, sexuality, relationships, love, and women as sex objects. The goal is to explain your family's values on this issue without making him feel like a pervert.
Tell your son that you won't try to prevent him from viewing these materials, but that you don't want him doing it in the family home (provided this is your opinion). Tell him that you could buy software to block materials your family finds offensive, but that you're giving him the chance to prove himself. If he continues to use your computer to view pornography, forbid him from using it entirely. He has to respect your disapproval of the messages this material sends and this approach shows that you have faith that he will do the right thing. Good luck.
