Reasons not to stay friends with your Ex- love

What to do? My ex-boyfriend (we'll call him Z.) has recently declared his intent to either meet a woman worthy of him or try to patch things up with me. When he annouced these intentions I could do nothing other than laugh uncontrolably. I couldn't help it. I was in shock. He has spent the last year or so talking about how I am not what he "wants in a wife" ( as you can tell we are still friends, neighbors, to be exact). I have spent the past year or so trying to move on romantically. And now this.

I am still in shock. More on this (potentially) humorous situation when I recover.