First of all, your boyfriend did nothing wrong by looking at porn, it's a completely natural thing that most men (and some women) do. It isn't cheating, it doesn't mean that he wants you to look like them, it's just something to watch. Nothing more, nothing less. I doubt that he did it to hurt you, far from it. Yes he lied to you about it but he was quite clearly trying to protect you and to be fair, it wasn't something that you should have asked him not to do, he can do what he likes when he is in the privacy of his own home. I just wonder how you know he did it, did you by any chance invade his privacy?
Your post was all about you and how you felt, how did he feel? Do you even know? Do you know how difficult it is watching someone that you love put themselves down over every little thing? Do you know how heartbreaking that is? Probably not. I don't meant to sound horrible but you were probably too wrapped up in your own feelings to even consider his. You were too busy worrying about the fact that he had lied about something as trivial as porn, you were too busy worrying about how you could be "better" that you forgot how difficult this situation was for him. I'll tell you something, it was no picnic for him either. When you have to put up with someones insecurities day in and day out, you lose your temper no matter how much you love them. You can see what a great person they are, you can see how beautiful they are but no matter how much you say it, they throw it back in your face and every time they do it, it completely breaks your heart.
No doubt about it, this is where all the problems began. I don't know how you found out about the porn but when things like this happen, the girlfriend tends to be snooping. I know it's not a nice thing, believe me i've been through the exact same thing but you can fix things. You two need to sit down and talk things through properly, talk about what happened in the past, what is happening now and where you want the relationship to go. If things carry on the way they do then you two will break up. I know it's unfair of him to blame you for all the arguments but if all the arguments started when the problem of porn came into the relationship, I can see where he is coming from but that doesn't make him right.
To me, it sounds like you two need to grow up. He needs to realise that when something goes wrong he can't act like a child and start calling people names, it's pathetic. You need to learn that porn isn't a bad thing, the porn isn't the problem, it's your own insecurities that caused the problems and together you can work it out, only if you two talk to each other. Your relationship isn't over yet, keep trying. If things don't work then it's time to move on.
I know i've been really harsh and very horrible but this involves your boyfriend too and you were too busy talking about how you felt and what he was doing, what about what you were doing and how he felt? Surely that is important too? I didn't do it to offend you, I didn't do it to be nasty, I just wanted you to realise that he has feelings too and he would have been hurting the same as you. You had to see it from a different perspective and i'm sorry if it upsets you in anyway, thats not what I intended to do. Believe it or not, I understand how you feel completely and I wish you the best of luck but what I said to you, someone else said to me and it did me the world of good. Don't give up, you two can get through this.