Uhm, you need to grow a spine. Tell him what you find acceptable, and what you don't. Don't having him delete crap in front of you, he's not a child. Treat him like and adult, and expect adult behavior in return. You're not his mother, so don't act like one.
Lay the law down and if he agrees to it, he agrees to it. If he doesn't, then listen to his counter-proposal and either accept that, counter it, or turn it down. It's a relationship, and no one person controls it. But you have your boundaries, and you need to enforce them.
And no, a virus didn't open the photo of his ex's vagina. He was looking at it, thinking about her, and wanking. Tell him he needs to be a big boy and not lie.
"Well, then," the Cat went on, "you see a dog growls when it's angry, and wags its tail when it's pleased. Now I growl when I'm pleased, and wag my tail when I'm angry. Therefore I'm mad."