How to be less insecure about him watching porn

I told my boyfriend a long time ago that I was uncomfortable with him watching porn. I was 16 then and now we are well into adulthood. Sometimes it comes up in arguments that he thinks this “rule” is ridiculous. Which I can understand to a certain extent. I use to watch it too when I was a teen so I can understand that sometimes you want to have a sexual experience with just yourself- maybe because it’s quicker or just because you want to explore some new things. It’s not that I feel that him watching porn is bad for the relationship it’s more so that I’m scared to be compared to those girls. Like their job is to be as appealing as possible and porn is made in a way to make them look as hot as possible. How can I compete. I get scared that I’ll be compared to them or even worse he’ll be thinking of those girls while having sex with me. I really do want to get over these insecurities because I think in some ways porn can be healthy. I am also just generally insecure and unsure of myself so I’d like to become more confident. How do I become more confident in myself to the point where I no longer feel jealous of those perfect girls in porn?