I don't have much to add, but I found that this paragraph, detailing some of the reasons to forgive, resonated with me:

Why forgive? What makes it the commendable thing to do at the appropriate time? It's not simply a matter of lifting the burden of toxic resentment or of immobilizing guilt, however beneficial that may be ethically and psychologically. It is not a merely therapeutic matter, as though this were just about you. Rather, when the requisite conditions are met, forgiveness is what a good person would seek because it expresses fundamental moral ideals. These include ideals of spiritual growth and renewal; truth-telling; mutual respectful address; responsibility and respect; reconciliation and peace.

I recommend you read the rest of Griswold's fascinating post—you won't forgive yourself if you don't. (You might also want to check out this podcast with Griswold at Philosophytalk.)