Should I tell my boyfriend I hate porn? Or do what he enjoys from time to time?

I had never seen porn until my boyfriend asked me to watch it with him before/during sex. We’re very open with each other but my boyfriend can be insecure about his sexual interests sometimes and I fear that he will be scared to open up with me about these things if I shot him down on this one. I tried it a few times, but honestly I hate porn. It for some reason turns me off. I think it’s because I know these people are (not the best) actors and I know there only doing it for show. He only ever has asked me to watch it a few times with him so it isn’t a huge inconvenience, but I can’t help that it turns me off. On the other hand, I can tell that he really really enjoys it.

Point is, how can I go about this lightly for my boyfriend?