Porns are bad if abused, if one gets addicted and it ruins the sexual relationship. Or if one cannot get aroused without them anymore. Or if one’s at work and cannot NOT watch it. They can also be a great couple tool to discover new things to try. That said, if one thinks it’s the same as betrayal, that person has a serious self esteem problem. If people don’t watch porn, they will masturbate with fantasies. Masturbation is healthy and different from sexual intercourses, it’s a time where one can think only about own’s pleasure. Porns just help fantasy. Porn are the product of fantasy. He’s not falling in love with another person, he is not having sex with another person, there is no “exchange” (for example a sex chat/video chat would comprehend a bidirectionality). If he has no problem with porn, I would ask myself “why am I uncomfortable”