When will the pain of cutting contact with an ex go away?

Why do I feel so bad, cutting contact?? My last post was about how someone broke off a long distance relationship with me, but wanted to remain friends. I tried, it’s not working for me, as I still have feelings for him. I told him I’m ending this friendship because I need space. He wasn’t happy about it & swears he will always be there for me. But, after I cut it off, I ran into him at a bar and it was awkward. He posted this on my Facebook wall:
I didn’t walk into anything. The fact is you’re in MY town and you know where I hang out. A random chance of us at the same spot would be probable, because you have no one else to hang out with tonight…and you desperately want to see who I was with. Id say more but I have some class, and don’t feel like explaining to the entire FB universe. Stop posting every emotional microism of your life online, thanks.” 
Yeah total douche move right?? So why do I hurt so much?? And when will the pain of cutting someone out of my life go away?? This is so hard for me. I hardly ever get dumped. Most of my relationships have ended on good terms. I feel so hurt, but it’s what I wanted. To go ahead and cut all contact!!!