I've been puzzled by this incident which happened years ago when I was married and I'm hoping MN can give me some insight. I'm now happily divorced.
One day my husband locked himself in the study and I went looking for him. I knocked on the door, he unlocked it and was furious at me for disturbing him. He had been using the PC and when I glanced at the screen one of the minimised tabs said "teenage anal sex". I didn't question what what he was looking at, at the time because he was yelling at me and I was begging for forgiveness. It's only in looking back that the "teenage" bit bothers me. The line between adult and child.