personally, I think a lot of men marry women for some of the wrong reasons which is why "porn" is always to blame.
most guys are unconformable with talking about fetishes and desires to their wife, so they just go on their usual schedule of "vanilla" sex, while they fantasize about whatever else it is that gets their rocks off.
whether its 18 year old girls or chicks peeing on each other, you can find your fantasy very easily. while a lot of women like to read romance novels, they don't get that a lot of men like to see the "real shit happen."
even in my case if my gf put out everyday i would still probably rub one off here or there... actually i know I would. sometimes when i can't fall asleep, or if i wake up 15 minutes before my alarm clock goes off and I had a good dream, etc.
either case, i think these women are misunderstanding the point... its better to pay $30/mo to jerkoff to some webcam porn then sit in AOL chat rooms and go bang chicks in the area and bring home a VD or worse.