Am I too cynical?

[Munchkin03]

Have you ever gotten back with an ex (after weeks, months, or years) after realizing that that person was the One?

I've never been one to run after an ex, and I cannot think of any break-ups that mended themselves into long-term relationships or marriage other than people who marry their HS sweetheart after decades of being married to other people.

I have a hard time believing that on-and-off relationships can actually sustain themselves into healthy partnerships. I'm in a good, healthy, long-term relationship (6 years tomorrow!), but I realized that I'm far too cynical about others' relationships. So...can those sort of things actually work themselves out?