I thin kyou've got to look into why it hurts you. You say it makes you feel not good enough, and ugly. But has he ever chosen to watch porn over having sex/spending time with you? I doubt it. Has he ever said that he wishes you were more like the girls he sees in the videos? If he has, get rid of him.
Generally men use porn as a prop. It's not about the individual girls, it's about the general idea of sex in general. I very much doubt he's watching it wishing your sex life was more like the sex in the videos.
No-one is perfect, as you say and that's why you don' like people having a go at you for things...but he's not perfect either. Watching porn is a completely natural thing for men and women in our society. He's not being perverse in any way, and it's important that men can have their own space and time, just as women do as well.
Imagine there was something you enjoyed doing, which brought you relief and relaxation and was something you ultimately enjoyed...now imagine your boyfriend coming along and completely irrationally telling you not to do it anymore because it upset him - for no valid reason. You're not going to happy about it. You miught try, but chances are you'd give in at some point because you can't really see a reason not to. So you lie about it, then they find out and suddenly it's not just the activity, it's the fact that they're lied as well.
You've got to face up to the fact that he's not going to stop watching it. It's not hurting anyone [apart from you, and you've already recognised your feelings are irrational] and he's only going to lie to you about it if you 'ban' him from doing it. I think you've just got be rational with yourself and be strong enough to stop yourself getting silly over it.
You've had problems with cheating etc in the past...that's a whole big issue. I'd say that really if you can't separate those relationships from this one then you need to take some time out. Relationships don't work unless you're happy with yourself as a person. With such deep seated anxiety and self-esteem issues, it sounds like you maybe need some time out to work out stuff about yourself because I think it'd benefit you, and because it's not fair that you're putting YOUR problems onto someone else.