What's your reasoning.

Not looking for any arguments or anything. I just wanna know why some females have a problem with their partners watching porn. If you're against watching porn in a relationship, and don't want or like that your partner watching then why? Personally, I don't see a problem with it.. Hell I'll even watch it with my partner. It doesn't bother me none. But to each their own.. But what's your reasoning.?  I'm just curious.