I never buy the "it's trivial and unimportant, so put up with it" line. If it's trivial they can give it up in order to spare your feelings. It's not as if you are controlling his every move otherwise, is it?
If it's important then that's another discussion and you may well be incompatible, because it most likely is a symptom of an underlying difference of values.
I cried endless tears over this one in my first marriage. I tried so hard to be "cool" with it and I just couldn't be.
Looking back I realise that it was part of a general pattern of total disrespect for me that undermined my self esteem and confidence and made me jealous.
Now I look far less like the women in the pictures than I used to and they are no threat to me. My partner and I have our ups and downs but I feel completely gorgeous and sexy with him.
If he uses porn he has the sense to keep it completely hidden but you know what - if I found him using it it might irritate me from a feminist point of view and I might tell him so, but it wouldn't hurt me or threaten our relationship...because the underlying dynamic, how he views women, everything is different.
So I would say forget about the abstract rights and wrongs and listen to your feelings and be true to them. If the relationship makes you feel miserable, insecure, and disrespected, then end it. You deserve to be with someone with whom you have mutual understanding and security.