Porn represents a failure of the girl's responsibility.
This just occurred to me when I was thinking about why it is that girls hate porn so much, why girlfriends shame their boyfriends for looking at it, and why they feel so offended by it. If a girl is upholding her end of the relationship, is attracted to you, and gives away sex and blowjobs like they're going out of style, you're not going to have much reason or desire left to look for naked girls online. Looking at porn is not a failure, or weakness of the masculine will, it's a sign that your sexual libido is not being satisfied by your partner. And she wants to shame you into believing you should be satisfied with whatever sexual crumbs she deems to throw your way. This hypothesis is based on the assumption that a man would always choose sex with a woman over porn, if given the choice.
Men's sexual drive is not something we put aside, and only pull out when it's convenient. It's built into our biology. That sex drive is what kept our species alive under some extremely unattractive circumstances. Just imagine how quickly we would have died out if our ancestors just decided he had a headache, rather than procreating with some unfuckable woman. So the point is, it's there, we're horny and not entirely discriminating. That's a feature, not a bug.
So when you're watching the final episodes of Mad Men, and you look over at your girlfriend and tell her, "I want your lips on my cock," and she says no, you don't think to yourself, welp, I tried, I guess it's not going to happen tonight. No, you call up a plate or you turn to porn. Porn never says no. And my point is that the billion dollar porn industry exists because women aren't sexually satisfying to men on a global scale. Think about what a massive failure that is. It dwarfs the global handyman industry, so I'm left to assume men are doing their part.
Women are taught that it's their body, their libido. They shouldn't have to do certain sex acts just because their partner wants them. But that doesn't work in a partnership. If I'm 150 lbs heavier than you, and you're put in charge of rationing the food, you damn well better not expect me to get by on the tiny amount of food you get by on. The female strategy seems to be to put their man on a sexual diet, and slowly decrease sex over time and hope he doesn't notice.
So if your girlfriend asks you why you look at porn, tell her it's because she doesn't satisfy all your sexual needs. And frankly, you should be looking for a girl who does.
TLDR wandering rant about how porn stepped in when women failed on the sexual part of a sexually exclusive relationship. Not, as they would put it, a failure of men to not look at it.