I believe another life lesson moment here is forgiveness. Can you forgive yourself and thus teach him forgiveness.
What I mean by forgiveness is: instead of sitting in - "This shouldn't have happened"; you acknowledge "what is", feel the feelings (disappointment, frustation, anger, pain), and then you take the next step to move forward.
Letting go of the "shoulds/shouldn'ts" and acknowledging that we all do what we do for all the reasons we do is what forgiveness really boils down to. I doesn't mean we won't feel the pain and we won't need to make some amends. It just means that we don't sit in the place that can't ever be changed and beat up ourselves (or the other person). We acknowledge what happened, feel all our feelings, and then let go by taking small steps forward.