SO creeping other girls?

Hey everyone! Please don't judge me for prying!!! My SO uses my laptop all the time, and I'll find browsers open of another woman's Facebook page. And then I will see my browser history, and it's like he has flipped through heaps of images. Then I will look at the girl and she will be magnificently stunning 😰 I mean I'm pretty but really?? What does this mean? Is doing this sort of thing something innocent or point to a higher thing? Please point me in the right direction, my mind is going crazy!!