Everyone repeat after me:
"I will not speak to my Ex. I will have no contact. I will block his number, email and IM. I will not pick up an unscreened phone call or a strange number."
Seriously. Its not easy to just stop talking to someone. Its just necessary. Kind of like someone with a drinking problem that has decided to quit drinking.
Don't grab another drink until you don't want another.
And like drinking, we all want another no matter how bad our last hang over was. We forget the pain and remember the pleasure.
ETA: We can only help you if you want to quit, and stop sneaking drinks now and again
