You sound like you have insecurity issues if you are afraid of some simple moving pictures. Why not talk to him about it? Or talk about why you are so insecure about him watching porn? Maybe you shouldn't read romance novels, which are soft porn for girls, anyway.
I have a long time interest in psychology, specializing in relationship dynamics for 30 years.
(Please note, we give the best advice we can based on the information given in a post. For better advice, please include the age of all romantic partners.)