I don't mind it unless it becomes a problem in the relationship. My ex ended up preferring whacking off to porn than sex with me so of course that didn't sit well but I don't have a problem with it in general. I understand men are visual creatures. There have been reports in the amount of cases of porn addiction increasing since accessibility has been so easy and like any addiction it needs to be treated accordingly if it gets to this point. Everything in moderation.
Some people are drains and some are radiators... Keep clear of the drains and hug the radiators!