Boyfriend and porn

I have really poor self esteem, I was overweight growing up and that really took a toll on my body. I've lost a lot of weight since then and come a long way, but I'm still not happy in my own skin. For this reason, I always feel inadequate. I always feel self conscious about my body and I have this fear in the back of my head that I won't be able to make my boyfriend happy. 

So that's where my dislike of porn comes in. When he watches it, it makes me feel like I can't satisfy him; like I'm not enough and he has to go outside our relationship to get what he needs. I've told him this about 2 or 3 times and every time he says "Ok I know it bothers you, I'll try to stop." And then a few weeks, a few months - whatever - goes by and here we are having this same discussion again. 

I know there are plenty of girls out there who are fine with something like this. I'm just not one of them. Am I being too sensitive? Am I stupid to think that I can ask him to stop? I don't wanna be that bitchy girlfriend that gets on his case non-stop. I just wanna know if this feeling is normal, or if I'm over reacting. 

Thanks. 

**update. 

Thanks you for your answers so far. I knew posting this I'd get a lot of totally opposite opinions. 

I know it is not his job to make me feel beautiful. I have been working in therapy to reach a place of feeling comfortable with myself because this is an issue that I struggle with on a daily basis. But know that I have felt insecure since 3rd grade and I am now a 20 year old. These issues just don't disappear over night. I want nothing more than to be happy in my own skin, but it's a journey and for me it's a long one. 

Thank you for your opinions.