Bete...I could have written much of what you wrote, and after leaving an NPD, I do know how you feel.
(Bad people do bad things. He can't be nice if he's doing bad things.)
There is a LOT about him that was nice...but he only accessed that part of him when he wanted/needed something...a lot like a child. If I look at it that way, it's easier to understand, and much more difficult to resent. NPD's are, in many way's like children who never grew up emotionally, because their sense of self was so completely muted by the time they were about 5, that is where they got stuck. Therefore, when he acted like a child (sweet, giving, funny, admiring) he did so because of a need/want. If I gave him what he wanted, he was satisfied, his sense of self intact.
(If he's not a bad person then you must be. He only did those things because you made him. You deserved it.)
He's not a bad person, but neither are you. He has a disorder and you did not 'make him'...he was made before you ever met him. You don't deserve how he treated you, but he didn't deserve how he was treated whilst growing up, either. Again, when he's angry because he hasn't gotten his way, he's returned to 5 year old status...he feels hurt, lost, unloved, abandoned. These are NOT good feelings for him because it beats against the very fear he lives with everyday--that he'll be 'found out'...that he's really NOT all that he is sure he is. It's not about imagining who he wants to be. It's about KNOWING who he is, and then having someone rip down that curtain and discovering what he's made himself believe is wrong, that HE is worthless, pointless, unremarkable, and the worst of adjectives, dismissable. I admit, this is an over-simplification...but, luckily for you, I don't want to delve to deeply into waters unnecessary to make you grasp what he was. You were with him long enough, and he (like many N's) TOLD you much of what he was, and probably without really understanding why he did.
The narcissistic 'rage' can happen if he's refused, or if he gets bored, (boredom is a killer because it gives him too much time to think..and soul-searching is not anything he wants a part of), bored with you, or a situation, or if you inadvertantly critisize him (and a criticism can be as simple as a question--as was said recently--because their feelings of worth are so fragile, anything can seem an insult..even things you've no thought could be) --all result in the 5 year old tantrum we're all familiar with. You didn't cause it. His childhood--for the most part--caused it.
(Even your own parents don't love you. The two people in the world guaranteed to love you and they despise you. Worthless.)
My father was so rarely allowed in the picture because my mother was a Narcissist... I often think I was trained to find one of my very own! lol Needless to say, I felt worthless as well. It took a long time to realize that fallacy, yet it all came back with my ex. I'm not starting at square one, although sometimes it feels like it. You aren't either. You're aware of what was going on with him, even as your mind tries to hurt you with the trickery you've felt years before. You ARE worthwhile. Believe THAT, because that is the truth.
(Keep playing the victim you mean. It's easier that way. Don't have to take responsibility for yourself. You can just hide away and tell yourself it's all their fault.)
You're not playing a victim...you were a victim. And being a victim is NEVER easy. Remember, human nature encourages us to find the 'easy button' in most things regarding our lives--if being a victim were easy, we'd all be doing it. And hiding, after the hurt you have experienced is absolutely natural...it's a comfort served a bit cold, but it helps...just not in the long term. And if you were condemning yourself to only hiding, you wouldn't be putting yourself out there, asking questions (even the hard ones that semi-attack you, as well). You know you don't want to do that...you want help understanding what happened, and you want to move on...
I too hadn't cried like I did for years before I broke up with my ex...and that it was my decision made no difference in the hurt. Sometimes the damaging thoughts 'what if?' 'why couldn't?' sneak into my mind and I feel the drag again...but it's getting easier to push them aside. And actually, understanding more of the reasons for why he was who he was, helps. It eases the resentment, the anger, and even the frustration.
It's gradual...but you'll get there. Promise.

Sorry if the reply was long!!