I have had the same problem with my boyfriend. When I first started going out with him six months ago, I tolerated him looking at other women, and have a collection of porn and stuff, but last month I snapped. I told him how unhappy I was, he didn't take all of it too lightly, but I told him to delete his porn, which he did...
But he still looks at pictures of women on the internet and stuff. Nearly every night I cry - it makes me feel like I don't have anything as good as they do. It's quite upsetting. I had a talk to him last night about it actually, it's like he understands, but is reluctant to change because he says it's something that all men do.
Why is that? When I first started going out with him I stopped looking at other men completely, regardless of whether they were on the internet or in real life - I would have thought he would have the same courtesy towards me.