Don't want to. I expressed an appropriate level of remorse to my friend fifteen years ago. Couldn't fathom why it wasn't enough for her.
During metta practice, I used her as the "difficult person." It turned out to be me. Retreats, dharma talks, meditations and voyages through bleak internal landscapes eventually revealed an inconvenient truth: I'd betrayed her.
Fifteen years ago that apology meant, "Sorry you're inflexible." "Sorry you're mad." "Sorry you don't understand my position."
Today, it means my heart breaks at the thought of the pain I inflicted.
I'm going to apologize.
And then forgive myself.