Talking from personal experience (and not nice personal experience, or anything I am proud of) sometimes when something arises with someone you love, it is just easier to shut your eyes, turn around, and walk away, because the things we see in the other person aren't things we couldn't learn to live with, but are things that we ourselves see as being too close to faults we sometimes see in ourselves. Being on the reciprocating end of such an act is never nice, but you have to believe that it is not a lack of love, that sometimes makes them walk away, but instead an act of preservation, to keep your memories of them less tainted.
Not sure if that helps you, but I hope in some way it helps you to understand what happened.