Marriage
Marriage is presented as the result of a number of different desires and necessities throughout the story, and it is the central theme around which both other themes and the plot as a whole revolve.
Maggie values her marriage to Amerigo and she is also very much in control of it, because she is the spouse with the financial wealth and because she is able to control the situations that spring up between them. The primary issue that threatens the marriage is the affair between Amerigo and Charlotte. However, Maggie does not want to end the marriage because this would result in the end of her father's marriage as well.
Charlotte views marriage as a financial expedient, marrying Adam for his money and the security he offers. Adam is marrying Charlotte for companionship, as he is lonely after his constant companion, Maggie, marries Amerigo.
Adultery
Amerigo and Charlotte have both a non-adulterous affair and an adulterous one although it is not always clear where the former ends and the latter begins. They feel they are being very careful and only speaking Italian to each other when they are in public but they are caught out when the storekeeper who overhears their romantic conversation happens to speak Italian too.
Their affair is the catalyst for Charlotte and Adam's return to America and also for Amerigo's realization that his wife is a formidable woman whom he should value far more than he does.
Secrets
There are many secrets kept by the characters in the book. The most damaging secret is that kept by Charlotte and Amerigo about their relationship. Neither confesses their affair prior to Amerigo's marriage, and they are even more determined to keep the affair a secret once they reignite their passions after Amerigo's wedding. Maggie keeps secret her discovery of the affair. She does this so that her father does not find out about Charlotte's infidelity, and she wants to protect him from hurt.
Father - Daughter Relationships
Adam and Maggie have a very strong, close bond that does not change even after Maggie is married. In fact, the bond becomes almost stronger. Maggie is concerned about Adam's loneliness and arranges for him to marry Charlotte; she also puts her own feelings about Charlotte aside after she learns of the affair, suggesting that the pair return to America, and keep her father's marriage intact. Theirs is an unselfish bond, perhaps the only unselfish relationship in the book.
Diplomacy
Maggie is blessed with the skill of diplomacy and arranges her family in a diplomatic way and thereby avoiding friction or devastating argument. She is able to remain polite and friendly to Charlotte despite her actions because she knows that this will help her father more than revealing the affair. She also knows that persuading Adam to return to America will both strengthen his relationship with Charlotte and remove Charlotte from Amerigo's life at the same time, thereby removing her as a threat to her marriage.
