I think what hurts most for you and other women in similar positions for you is that he keeps choosing to watch it over choosing to respect your wishes and boundaries. He lies to you about watching it. In a way he's putting these other women above your emotional needs, so it feels like he's putting other women above you. It's a very primal feeling of rejection that can feel like being cheated on. Porn can take a hold of some people to the point of destroying a relationship with lies and sometimes loss of a sex life. Your man knows how much it hurts you but he can't stop because he craves it like a drug so he keeps lying. Drugs always come first. He's not going to stop until he realizes that he has a problem that prioritizes his sexual drive for porn over your well being. A lot of people say cheating is a deal breaker but those same people fail to recognize that mass porn consumption can feel like cheating too, especially with all the lies and primal feelings of rejection that can come with it. I want you to know that it's okay for you to feel upset about this and it's okay for you to not accept it as a part of your relationship. There is nothing wrong with you and you don't have to "understand" how others are accepting of porn in relationships.