The consequences of this are worse than you might think. The thin end of the wedge is less enjoyment during sex. Jon’s dissatisfaction with real life sex is something he has in common with a lot of habitual porn users. In his book, The Brain That Changes Itself, the psychiatrist Norman Doidge writes about a phenomenon he began to notice among his male patients in the mid 1990s. They watched porn – “everybody does,” they told Doidge – and were experiencing “increasing difficulty in being turned on by their actual sexual partners, though they still considered them attractive.” They found themselves having to fantastise about porn scenes to get turned on.