Am I overreacting?

A coworker of my fiance has been sending him a lot of porn. I found this so strange. What guy sends another guy porn? Is this normal? Some of them were jokes/images, but others were literally straight up minutes and minutes of porn videos. My fiancé didn’t see a problem with it, said I’m overreacting. Not only do I feel disrespected, I also just think it’s plain weird and I don’t know what to do..