I can't be sure. I probably shouldn't speculate. It just seems common that they don't really believe we forgive them and when we get insecure they think we'll never "get over it" or they'll never be able to "do enough to make us happy".
Now, being the great DB-ers we are, we know that no one can make us happy but ourselves. Without work though, that gets lost and we fall into the same dynamics that led to problems in the first place. Make sense?