Accept what has happened and face the reality. Cut off any form of contact with this ex partner as a way of avoiding memories. Socialize with other people in different societies and seek for help from a counselor. Check out http://www.ehow.com/how_4404152_over-nasty-break-up-fast.html for more tips on this.
It depends, for me because of the reason my ex broke up with me we could still be friends. We had an off and on relationship so we already had the friendship stuff going on, but we aren't as close anymore and it took me a long time before I could stand to see her in person. We do text every couple of months and that's fine with me because as a friend she was very important to me so I didn't want to totally lose her. It may have taken me longer to get over her, but that's what I wanted to do and it worked out ok.