What are the rules that govern a break up?  When a boyfriend and girlfriend decide to move on, can or should they still see each other "as friends"?  Is one "allowed" to be jealous when the other starts dating again?

My own opinion is that a break should be clean and complete, at least for the first, oh, year or so, while the wounds are still fresh.  I don't think you can or should see each other until you are truly and completely OVER each other.  But that's just me.