My bf is addicted on other girls photos?

Few months ago, I saw some pictures of other girls on his phone, many girls with swimsuit, little dresses, heels etc. He said he will delete them all, and so he did. Yesterday, I found on his laptop same photos from his (girl) friends and from 2 of my best friends. All photos were focused on legs. I know he likes female legs a lot. He said he doesnt know why these photos are there he promised it will never happen again. I think that I have to leave from this relationship. What do you think?