A reader writes:

It strikes me that Ross bases his argument on the assumption that the porn watching offends the non-watching partner. In that case I can understand his claim that the watching constitutes a form of adultery, though I strongly disagree. Surely it is, at most, an act of dishonesty -- one that has to be weighed against the right to privacy that persists even within the closest of relationships.

But, of course, his original assumption doesn't hold in many cases. I watch porn; so does my girlfriend. Sometimes together, sometimes alone. Individually, it's a turn-on; mutually, a happy addition to our sex lives. We're hardly unique. The key is that we both know about the other's porn-watching and heartily approve of it. There's no betrayal involved. There's friendship. And some other delightful things that also begin with F.

More broadly, Ross's stance raises the question of what constitutes an adult relationship. Images on paper or screen cannot possibly form the basis of a relationship, adult or otherwise; and without a relationship, surely there can be no adultery. More importantly, his stance would force "offending" porn-watchers to one of two conclusions: continued deception of their partner -- a sort of sexual stealing-from-the-cookie-jar -- or submission to their partner's sense of propriety -- what we used to call peer pressure. Both are infantilizing.