We really need to do a thread over men, porn, and relationship issues about it.
Secure women usually do not have a problem with their men watching porn, so long as it doesn't interfere with their relationship and sex life.
However, a woman's insecurities about their man watching porn can cause relationship issues and poor quality sex. Thus making it harder to determine if it's the porn or the woman's insecurities that is causing the problems.
I would say that it's far more likely for a woman's insecurities to be the root of the problem than a man's moderate interest in porn. Only on rare occasions do men have a severe porn addiction.
To the OP... have you thought to talk about your SO in regards to the porn? More from the angle of curiosity?
I like red-heads... but that doesn't keep me from finding my light-brown haired bf attractive. I like porn portraying group sex (sometimes)... but that doesn't mean I'd want to share myself with anyone other than my bf.
As for him looking at other women... that's a whole other thing... and something men have very little control over. He will look... it's an instinctive thing. The fact that he looks back at you shows the choice he makes over and over again --- wow, that girl's pretty... but I like the one I'm with.
As a general rule... I've noticed that women tend to infer far more from a man's actions than the guy actually gave thought to when he did the action.
For example... you sit next to your guy... he gets up and moves a few inches away. You may think he doesn't like you anymore... he doesn't crave intimacy... the relationship is headed to collapse... so you start to worry and watch him more closely.
Meanwhile.. the guy got up and moved because the AC is broke... it's hot as hell.. and he just wanted to watch tv without burning up from the added temp of your body.
If you ask him why he isn't intimate anymore... it will lead to a long conversation that may weaken the relationship and put doubt in his mind. However, if you asked him why he moved... he'd tell you because it's too hot to sit that close to you.
In this case... asking him why he favors smaller women may never explain what's really going on. Ask him why he watches porn... what he likes about it. You'll probably get closer to the root of what's really going on.
"The weakest soul, knowing its own weakness, and believing this truth that strength can only be developed by effort and practice, will, thus believing, at once begin to exert itself, and, adding effort to effort, patience to patience, and strength to strength, will never cease to develop, and will at last grow divinely strong."
- James Allen