[wayner]

For anyone having hard time letting go, forgiving or whatever:

I believe that one ( perhaps just one mind you) aspect of holding a grudge or being stuck in the past is you "self's" way of telling you that there is still a problem.

The subconscious realization that this could happen again and "WE" don't know what we would do about it.
A vulnerability or naivety. I personally believe that until one can establish healthy boundaries, the vulnerability remains and the past lingers.