You are protected, in short, by your ability to love!
Isn't it funny how the memories you cherish before a breakup can become your worst enemies afterwards? The thoughts you loved to think about, the memories you wanted to hold up to the light and view from every angle--it suddenly seems a lot safer to lock them in a box, far from the light of day and throw away the key. It's not an act of bitterness. It's an act if self-preservation. It's not always a bad idea to stay behind the window and look out at life instead, is it?