His marriage to Terentia was for convenience

One of the most interesting facts about Cicero is that his marriage to Terentia was for convenience. Cicero married Terentia in 79 BC when he was probably 27 years old. It was a marriage of convenience, according to upper-class standards of the day, but it lasted for nearly 30 years. Terentia's family was affluent, most likely from the plebeian aristocratic line of Terenti Varrone, and so met Cicero's political ambitions in both economic and social dimensions. She had a half-sister named Fabia, who had been a Vestal Virgin as a child, a tremendous distinction. Terentia was a strong-willed woman who was more interested in her husband's political career than in family concerns.

Cicero's letters to Terentia were shorter and colder in the 50s BC. He complained to his friends that Terentia had betrayed him, but he didn't say how. Perhaps the marriage could not withstand the strain of Rome's political upheaval, Cicero's engagement in it, and several other disagreements between the two. The divorce appears to have occurred in 51 BC or shortly after. Cicero married Publilia, a young girl who had been his ward, in 46 or 45 BC. Cicero is said to have required her money, especially after having to return Terentia's dowry, who hailed from a wealthy family. This marriage was short-lived.