The teaching starts off easy. Forgive everyone. Then it adds, forgive yourself, which I found much harder and had not thought of as part of the deal.
There are two levels to it. Forgiveness by the mind and forgiveness by the heart. The mind is quick. It can forgive somebody in a meeting and be perfectly pleasant to them by lunch. The heart works slower and keeps a copy of everything.
My Professor also gave us a test for when you should not forgive. Ask what your forgiveness lets happen next. If nobody else is affected, forgive. If forgiving would be bad for other people, do not. He used deliberate murder as the example.
That moved the whole question out of my chest and into my head, which I did not enjoy. It stops being about how much I am hurting. It becomes about what I am allowing.
तेजः क्षमा धृतिः शौचमद्रोहो नातिमानिता । भवन्ति सम्पदं दैवीमभिजातस्य भारत ॥
tejah kshama dhritih shaucham adroho natimanita bhavanti sampadam daivim abhijatasya bharata
Vigour, forgiveness, fortitude, cleanliness, freedom from envy, freedom from craving honour. These belong to a person of divine nature.
The class also gave me the trick that makes any of this possible. Judge the action and leave the person alone. They are two different things. I tend to decide somebody is difficult after watching about four minutes of their life, and then I file them under difficult for good.
My mind has forgiven a long list of people. My heart is still reading through the list.