Saying it is 'disrespectful' because he is looking at other women is frankly a bit silly. Take away porn and people still fantasise about other people or situations when they masturbate, and when they have sex at times. What's next, demanding a list of every sexual thought a partner had since the relationship commenced AND disclosing all of your own? I hope not!
Women use sex toys as it is better or less physical effort. Men use porn as it is less mental effort. Unlike Mr Rabbit though, porn has a negative side. In artificially providing an arousing visual focus, it can gradually deprive men of their own sexual world of fantasy & imagination. They no longer need to be aroused to seek sexual gratification. It becomes almost not about sex. The mental effort is removed. This is why porn use can cause erectile dysfunction - sex and the mental process of arousal becomes alien, the brain is re-wired to respond to porn. That would be my concern about porn use. If it gets excessive or becomes a crutch / go to every time, then it isn't an indulgence, it is a problem - just as being unable to enjoy a social occasion without drink or drugs is a problem.
People are perfectly entitled to think porn is exploitative and immoral, or a harmless indulgence, or anything in between. Personally, I think there are shades of grey and it depends entirely on the content - but that is personal opinion, not something I would seek to inflict on a partner like a censor.
As with eating meat, drinking, using drugs etc... it is one of those things where if you want something absolute from a partner, then you need to set that expectation very clearly up front. If you don't, then trying to later will probably be openly or privately ignored, and then you have to decide whether to live with it or not.