BF watching porn

Norma
I know that every guy does it. Even guys who are in relationships or married. But I'm having a really difficult time being comfortable with the fact that my long time boyfriend jerks off to porn...it makes me feel insecure, vulnerable, and like I'm not good enough or sexy enough for him. Again, I KNOW him watching porn does not mean he's not satisfied but it's hard to be okay with it. 
Advice?