People often forget that a failed relationship doesn't reflect failure of the people in it. Sometimes things just don't work out, through no fault of either person, or through the fault of both people due to timing, lifestyles, backgrounds, etc. And yet, when a relationship falls, it seems natural to question oneself's worth and whether we had tried hard enough. It's a step towards maturity to realize that things happen, and if you've already tried "hard enough", then that break-up was a decision to let it go. But it doesn't mean you're a terrible person (unless you did terrible things).