Boyfriend watching porn..

Okay so today my boyfriend admitted to me that he watches porn occasionally which didn't surprise me obviously but still it felt weird hearing him actually say it. So for some reason I can't help myself and idk why it bothers me so much. I told him it kinda bothers me and he was like I don't see a problem with it I don't care about those girls or whatever.. But EVERYTIME I think about him watching it and doing his Business to it I just can't help think that he's staring at those women and thinking why I don't look like them.. I realize this makes me seem weird but I feel like it's probably because I'm so insecure and I didn't even realize it. Also were in a long distance relationship so I really can't blame him at all , I just need like something to calm me down a little because I realize it's perfectly  normal I just can't help my feelings .. Thank you :(((