Well, here is how I handle it. And yes, it absolutely devastates me, but I have a method that seems to work. Firstly, I need to know -why- it ended. None of the vague, wishy-washy, cowardice, but a truthful answer. This will allow me to pick up all the pieces, and put them into a box, label it, and put it away. If I -know- what it is, then theres no reason to keep reopening it in my mind, going back over and over to try to make sense of it all.. it all merges into one powerful truth. This truth is now written in my psyche, and I mute all of the chatter. The chatter no longer matters. There is no reason to check his facebook profile anymore for answers, or send him a drunken IM pleading that he explain anything. Its all explained. (Now what sucks is when they learn what I do here, and try to complicate it and work their way back in, instilling doubt. Fuckers.)
Now that I have put it all away, and have stopped picking through the pieces, it begins to fade. Some visualization also helps. I had one absolute nightmare of a time getting over someone once because he planted these little bombs in the foundation and structure of our relationship the whole time, that he detonated once I wanted to call it quits. I will not go into detail because it hurts too much to recall it. But he did terrible things the entire time, just to feel like he had some footing, some control. After I left, he would try to come back and say he had lied about it. Then later he would say that he had not lied about it. This dragged out for months until I was so mentally unstable that I collapsed on my bathroom floor having blacked out from a panic attack. He completely removed my own footing on reality at this point. It took more effort to box this one, because there was no way of knowing what was real and what was a lie. I determined he was all a lie, I never knew him, and he had been faking his entire personality the whole time (which actually ended up being quite true).
The way I got past this was through lots of visualization. I found a fantasy map. It was one of those with lots of hills, lakes, rivers, islands.. very lovely, very vast.. After I disposed of anything that reminded me of him (including lotions that I'd had around that time) I started to envision that everything that happened between us took place on a particular part of that map. I poured all of the nastiness into it. I then imagined myself leaving it all behind in the middle of the night. There was nothing left to say. I packed my things and I boarded a ship, then I traveled across some land.. I boarded another ship. The journey I visualized, in detail, and I ended up far, far away, alone, in a nice cottage, with a lovely garden, in a place that he could never find me - a place he would never know of. He couldn't hurt me anymore.
I did not give in and contact him first. If you do, its like hitting a reset button, which I realized with a previous ex. Then you have to start the process of getting over them all over again. A voice, a smell.. all of these things trigger that brain chemistry that was causing an addiction to them in your mind. Only removing yourself and not looking back will assure that you don't relapse.