Speaking of porn, Fr. Bryce Sibley directed me to an article on how internet porn affects relationships. Here's an editorial by Naomi Wolf, saying much the same thing:

For most of human history, erotic images have been reflections of, or celebrations of, or substitutes for, real naked women. For the first time in human history, the images’ power and allure have supplanted that of real naked women. Today, real naked women are just bad porn.

JPII's Theology of the Body actually predicts this. I might make the effort to track down some relevant sections later on.