I feel like my fiancé is cheating..

Kiana • 22 years old. Nursing Major. Happily married. 👑💍
My fiancé "claims" that he's faithful. He says that he doesn't look at girls or look at videos of girls.. But I feel like secretly he does look girls up. He also tells me that he only looks at me and that I'm beautiful, but I feel like he likes other girls. Especially because they're prettier than me. I don't think he's being honest with me.