I think the best thing to do is stay busy, and I don't mean busy thinking about what you did wrong.
Experience has taught me that people who leave without even the courtesy of an explanation were up to no good, and if they couldn't be decent enough as human beings to put the cards on the table - they were the last thing I wanted back in my life. In short, I considered it to be a nightmare averted and I was thankful I hadn't wasted a huge chunk of my life on such a trifling fool.
THEN. I went and got me some tight pants, a nice form fitting shirt, rang my buddy and went out and had some fun.
Amazing how fast getting hit on makes a bad bf disappear from memory. It's been called "get back on the horse". You don't have to leave with anyone, but it's nice to flirt and remind yourself that you can replace that fool in a minute. Bust out your inner "Beyonce"!! Put that fool in a box to the left.
I think you need to quit feeling hurt and go ahead and be insulted and yes, a little mad. You strike me as a nice guy, he owed you better than that. Not angry as in "Imma whup his ass". Angry as in "I'm a good guy, and THAT was a mistake I will make sure he lives to regret in time."
Go to the gym, and channel all that frustration into something worth while. Nothing says I'm over you like a hot new 6 pack. Spend some quality time on you. Spend some quality time with friends, but for the sake of all that is holy (Madonna) I wouldn't waste another hot second with his name on my lips or his face in my head.
It's about self respect. Don't let him take yours on the way out.
There. LOL you asked.