There is no "The One". That's just fantasy made up in your mind. There are any number of potentially compatible partners out there who, for reasons of bad timing, immaturity, being already taken, and many other reasons, are not able to form a viable relationship. This is all that happened to you. Don't make it more than it is, you'll be happier for it.
Ppl are telling you to break all contact b/c its generally the best and fastest way to get over an emotional connection to someone. Anyone who has been through a difficult and prolonged breakup will tell you exactly the same thing.
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh