Good reason to be upset?

So I was on my bf phone and saw that the past few weeks he’s been watching porn and looking up naked girl pics online. He says it’s usually when I’m not home and at work, but yesterday I was only gone from the house for an hour, and he watched porn yesterday, he said it was while I was gone though. Him and his brother said that when a guys in the mood, he’s just gotta take care of it, but it personally makes me feel hella insecure, I mean I’m heavier and don’t have the nicest body, so it makes me feel like there’s something wrong with the way i look, or like he doesn’t enjoy sex with me. He said that’s not what it is at all and he thinks I’m the most beautiful, sexiest, cutest woman and that it’s not because he doesn’t enjoy sex with me, he just doesn’t feel like having sex and the work and energy that goes into it all the time, I mean we still have sex at least 3 or more times a week, but it still makes me feel insecure. Do you guys think I’m just overreacting and thinking to much into it, or do you think I’m rightfully feeling the way I’m feeling?