I'll try and answer this one...I had a similar issue in my past relationship, the only difference is I thought it was perfectly natural to look at porn myself...as long as I kept it in check. i.e. (not looking at it ALL the time) I told her that the reason I did look at it was that I am just horny that much and I so this was my way of dealing with it, but my g/f did NOT want me looking at it at all, she would even get mad if I looked at a Playboy, it was bad, to me anyways, so I told her that I felt like we needed to at least be more physical in the relationship, even if it wasn't sex all the time. She ended up telling me that she felt pressured to have sex with me which confused the heck out of me since I had NEVER pressured her for sex, in fact when we had that discussion we hadn't had sex in about a month...sorry I kind of rambled on there...

To make a long story short, I think it's a perfectly natural thing to WANT to look at porn. I think if it hasn't affected the relationship at all I would continue with what you're doing. Maybe tell her (if she knows you look) that you would stop if she ever asked you to or if it ever affected the relationship, maybe she will express her true feelings about it, good or bad. If she says she would want you to stop, then from what you are saying I think it would be easier for you as it would be motivation for you to stop if you really LOVE her like you are saying, but I know it would be hard, as I did try and stop for my ex and it wasn't easy at all.