Porn freaks me out

I know my boyfriend watches porn (mainly while I'm at work) and I haven't exactly talked to him, he knows I know he watches it but I don't know how to explain that it kinda freaks me out that he watches it and then after taking forever to answer me says he was doing something else and also that he's really tired usually but says it's from work and I know he's also tired from work but sometimes it isn't just like one video that I come across....please any advice will be great