I tend to go along with letting destiny play its part. In a situation like this it might be better to shut the door, get on with life and look for its nice qualities: happiness, friendship, passion, and if circumstances dictate, renew a former relationship if it seems workable.

Trouble is when couples break up then return no matter what sort of flame they are, the return comes with the history. Can't be avoided. It's possible if the break up was over some "offence" and the offending party has truly repented, then it might work but I'd say that's pretty rare. It'll never be like a new relationship. It won't start with a clean sheet....because the people already think they know each other. Discovery and exploration is limited to what's happened between. People don't change overnight.