This is just simple truth about divorce as you spoken 99% of my mind. I see Divorce just as just a simple mistake, its error was not corrected at the point of occurance. Person who make mistake of divorce can't still correct it's error by reuniting as long they are both alive and have come to agree where they disagree.
I don't have any statistical data at hand though, but I have got the impression those couples who decided to break up and separste their ways are very unlikely to reunite, it is possible, but not likely.
Usually, when divorced people start again by their own they may start dating and hanging around with other people they would like to start a new relationship.
Those stories about divorced couples reunited are something out of a Hollywood movie, it has kind of been implied into the popular culture of the population through the broadcast in the media. It is important to realize, it is not the norm but rather the exception when a couple come together again.
Actually, it is funny you mention this scenario, because I have got a cousin who may actuslly get together with his spouse after years of separation, if they do, it would be something like a little miracle.