Is it cheating?

Hey ladies so I'm really upset right now. I was using my bfs phone when I came across a tumblr account that he had bookmarked. The tumblr was a gallery of nude pictures of someone I went to high school with and we both know her. I know that guys look at porn but it just bothers me as I don't look at dick pics from his friends. It makes me feel even more fat and undesirable in this pregnancy. Any advice would really help. Thx