Ah, it was a lover. Well, I have no idea how old you are, but adults are usually mature. They rarely change, and when and if this person comes a knocking and says they've changed, they're likely lying. Change takes many years. As for young love... well, I'd estimate less than one percent of it becomes lasting. For your sake, it's time to move on and leave this person in the dust. Let them wallow in their sorrow... and likely pitiful mood.