Closure with myself

The last time I cried about it was the day of graduation.
I'm pretty sure that was everything combined - from knowing that I probably wasn't going to see her for at least years if not ever again, from knowing that she had almost blindly found someone to take my place, the fact that she acted completely oblivious to the fact that everything she was doing was breaking me down more every time, from knowing that she had just thrown me out of her life completely... I couldn't help being bitter and angry. It was supposed to be me, it should have been me, how could it not be me?
This was no ordinary cry. It was what I had been holding back for almost a month. The anger over having to deal with seeing her flaunt the person she left me for all around campus, introducing her to people she never took the time to introduce me to, blah blah blah.

And after that meltdown I finally realized something: The reason I'm so upset over what she's done and how she's hurt me and boo hoo is that the two of us never had closure. But why? Why is it so hard to come to an understanding about how each of us have hurt each other, and about what we expect from each other in the future?

Because I'm dealing with a narcissist.
I've realized over the past month that I can't sit here and wait for closure, because closure would involve several things a narcissist is incapable of: First, an ability to empathize with how the other person is feeling. Second, an ability to realize one's own mistakes. Third, the ability to give up a certain level of selfishness.
If my ex was capable of any of those things, the two of us would have had closure months ago. Does a person have control over their narcissism? I don't know, but I accept her for how she is. But I also have to accept the fact that we will probably never be able to talk about closure because she can't empathize with me. (But she'll be able to once someone does the same things to her that she did to me.)

So, what can I do?
I'm no longer in pain from the situation, but sometimes it pops back up in my mind and I find myself wondering if I'll ever be friends or what have you with her ever again. Is it possible?
I don't know. But I do know that I have found closure with myself and defined what it means. It's a sad fact, but I have finally accepted that I will never get what I need from her. She won't be be willing to give me what I need of her, because she is too self-centered as of now. If she wasn't she couldn't have ever done the things she did. But who knows if that will always be the case?

When it isn't any longer, I'll be ready.