While I respect your point-of-view, FadedRose, I don't think confronting is the right answer in this situation. It will only lead to a big fight, he will get defensive. He won't listen, he'll just put up a wall. Instead, sit down and talk to him calmly and rationally about this. Tell him how much this bothers you and that you feel less desirable because of it. Write down your feelings beforehand so you are clear about what you want to say and don't get caught up with the less important things. Tell him that lying about it only makes things worse. Lies, even to protect the other person and avoid a fight, drive wedges between people. If he gets defensive, don't get angry and defensive in response. Stay calm, otherwise the situation will only escalate. He may just not realize how much this bothers you.
Just because he looks at porn does not make him a sex addict. Looking at it once in a while isn't abnormal. When it gets to be a problem is when they can't stop, they start lying about it and hiding it (ahem...), when they start acting on their impulses, and when it interferes with intimacy with their partner. Just because he has a problem, doesn't make him an addict, but it can move in that direction if it gets out of control--although I'm not saying that it has in this situation.
It's up to you whether you break up with him for this or not. If this is a deal-breaker for you, that's your call. If it isn't, that's fine, too. It depends on how much this bothers you and whether that matters to him or not. If your feelings don't matter to him, then it doesn't really matter what the topic is. If he is keeping secrets and hiding things, that is something that needs to change right now. Personally, I think this has more to do with you feeling disrespected than it does with porn. You could replace porn with a number of things, but him disregarding your feelings would still make it a major issue for you. The fact that it relates to intimacy and your self-esteem only makes the issue worse.
Also, please understand that he does not look at porn because you aren't good enough or that you don't have enough sex or that the sex is getting boring. That's not it. I don't think his looking at porn has anything to do with you and you need to stop thinking that it is. Even if he stops looking at porn completely or you dump him because of it, if you don't stop thinking that it's your fault, you will still feel inadequate with him or any other guy.
Again, my advice is not to be confrontational about this. Be open and honest with your thoughts and feelings and allow him to express his, as well. I'm not saying you should let him dominate the conversation or let him walk all over you. Be direct and firm, but calm. I think it has a greater chance of a positive outcome than if you treated it like an intervention.
Best of luck to both of you. Please let us know how things work out.