The third story in
For Your Eyes Only.
This story has no spies, no guns, no supervillains, no global conspiracies, and yet it might be one of the most significant pieces Ian Fleming ever wrote about James Bond.
Bond is sitting on a sofa, after a dinner party, talking with the Colonial Governor. After Bond (who despises small talk) makes a comment about marrying a stewardess, the Governor launches into a story of one of his old coworkers, and it is this tale, told in the older man's voice, that comprises the bulk of the short story.
In brief, it is the story of a young Diplomatic Service man who marries a flight attendant. When she becomes disillusioned with her less-than-flashy life and her uxorious husband, she has a blatant affair. It ruins her husband, who is eventually transferred to Washington for six months.
When he returns, he ruthlessly crushes her spirit much as she did his -- but privately, over the course of a year. In the end he leaves her financially and emotionally ruined, but pays the price of the coarsening of his soul. In the end, she hits bottom and slowly recovers, even finding happiness.
The crux of the story is the emotional phenomenon the Governor calls the Quantum of Solace, the smallest unit of human compassion that two people can have. As long as that compassion exists, people can survive, but when it is gone, when your partner no longer cares about your essential humanity, the relationship is over.
At the end of the story Bond is depressed, and suddenly finds his life of adventure to be fundamentally boring and unfulfilling compared to the real human drama the Governor has told him about.
The unwritten part of the story, the essential truth never spelled out in so many words but clear to anyone who has spent the last week reading the original Bond books is this --