I'm not against porn per se. I used to look at porn alone and with my partner.
For me porn is about action, that's all.
My problems with porn started when I realised that for men, porn in essense, means fantasizing about having sex with the women in the pictures/movies. And the desire is based on the way they look.
Now, I'm not the most secure woman on earth, but I know I'm attractive.
But knowing that for him, I'm just one of the girls he would have sex with, who just happens to be there. Does he have to restrain himself and resist temptation to be with better looking women? I think that feeling made me insecure, rather than the other way round.
The fact that I don't want to be (sexually) with anyone else but him, doesn't help either.