What is the main conflict in Our Man in Havana by Graham Greene?

Jim is a British vacuum cleaner salesman in Havana, Cuba. Jim's wife has left him alone with their young daughter, Milly. His business is failing and struggles to provide for his daughter's many wants. For her seventeenth birthday, Milly wants a horse and Wormold agrees to give it to her, despite not knowing how he will pay for it. Then he meets a man who offers him a job as a spy for the British government. He has no qualifications for the job but he does not let this stop him. He begins to write fake reports not based on any real intelligence gathering. He also recruits fake agents and collects their salaries. He feels somewhat guilty doing this and figures he will be caught at any time. He collects the money and saves it in order to give Milly a better life.

The Secret Service send him a secretary, Beatrice. At first he tries to hide his actions from her but eventually he confesses to her. To his surprise she understands. When his actions come to light, he is forced to leave Cuba and move back to England. At the end of the story Wormold faces the Chief of the Secret Service and is not reprimanded. In fact, he is given a position training other agents and awarded an O.B.E.