Boyfriend and his porn.

My boy has many many naughty pictures of women on his phone and laptop. I don't know how I should feel about it. I don't know if it's okay for him to have it or not. He knows I know. I've told him before how I felt about it. It makes me feel insecure, like I'm not good enough. He knows it does. He's deleted it once for me but obviously that didn't last long. My heart throbs and I want to cry. It hurts. Is it a boys will be boys situation or? I have a hard time trusting him sometimes due to past events and this isn't helping. Opinions are needed.