My 46 M fiancée made an inappropriate comment about his F30 coworker and I now have self esteem issues in the relationship. Is it weird I now don’t feel the same and want to leave?

r/

My fiancee volunteered to me one day that his female coworker is a but-her face (good body, ugly face). He also talked about her wearing skimpy clothes in training and would often bring her up in conversations telling me about their interactions. She is small and very fit. I am tall and curvy. I feel that it’s disrespectful to say that about her to
me. I feel like something is off. My confidence in myself in this relationship is shook. I’m worried there’s something there and it’s hard when he goes to work cause she’s there. I don’t want to be intimate and am contemplating ending it. Is this rational?

TL;DR; : he made inappropriate comments about his coworker. Am I being too sensitive?