Just curious but is it the type of media involved - the internet? Would you react the same if he was reading The Sun, which is essentially the same, but in print rather than on a computer screen?
Considering the type of material available within a few keystrokes, if the Currant Bun is the only thing he has been surfing then you should thank yourself lucky you have a red-blooded male with an eye for the fairer sex, its not as if this is what is cooloquially known as 'hard core', I wouldn't be too worried about it.
People often get worked up about stuff like this but its stupid. I know my good lady has the hots for George Clooney but a) the chance of her meeting him and b) them running off together are so far remote its laughable. I allow her to indulge in that, and just occasionally let her know she's not quite as hot as Uma Thurman.....keeps everything in perspective!