Catherine’s calm was not the absence of feeling. It was the result of years of endurance.
And maybe that is the final lesson in all of this: a family does not survive on a marriage certificate alone. It survives on respect, gratitude, and daily responsibility. The moment one person starts believing the other will never leave is often the very moment they come closest to losing them.
If there were any advice left for David, it would be simple. Accept the consequences of your own decisions. Life does not always give people the chance to go back and correct their mistakes, but it does give them the chance to become wiser because of them.