Ladies I need your opinion!!!

Is it just me or would you also be mad at your boyfriend if he lied straight to your face when you asked him if he watches porn?... Like I had to get the truth out of my boyfriend because he lied to me and said he did it to pictures of me when clearly he has nothing like that of me to do so.. But I also knew he was lying anyways because well, girls always find out the truth. Is it wrong to be mad that he does that behind my back? Because I know that shit bugs me and makes me feel I don't know... insecure about myself, I recently found porn on his usb I was gonna return to him today when I see him... Should I discuss and make a big fuss about it... Or just let it slide and not bring it up? Ugh this'll bug me for a while that's forsure😒