porn is like a gateway drug. The "soft" stuff gets boring, so they have to keep getting "edgy-er" and upping the game. It becomes addictive and destructive. My H is supposedly recovering and abstaining from it, but I have found things he has been checking out online. Some really sick stuff too. He has gone on to EA's/PA's and all kinds of other "paid for" activities outside of marriage.
As for your boys, I would try to emphasize the point that it is not realistic and is disrespectful to women. My H's mom thought there was nothing wrong with it -actually considered him a "healthy" male because of it. ick.