Bandini married Marie de los Dolores Estudillo on November 20, 1822. She was born c. 1808, daughter of Captain
José María Estudillo. They had three daughters,
Arcadia, Ysidora, and Josefa, and two sons, Juanito and one who died in childhood. Bandini's second wife was Refugia Argüello, daughter of
Santiago Argüello. They had three sons, Juan de la Cruz, Alfredo, and Arturo, and two daughters, Dolores and Victoria. Bandini built a large U-shaped house, Casa de Bandini, in 1829. Initially it had 12 rooms and was one-story. Bandini was forced to sell his house in 1859 due to financial losses. Part of the building was converted into a store. His house was later converted to the
Cosmopolitan Hotel in 1869, with a second story and wraparound porch added. The house still stands in Old Town San Diego, at the east corner of the town square, and has recently been fully remodeled and reopened as a hotel and restaurant. Originally the house and hotel were not stuccoed—that was added in modern times to make it look "Spanish Colonial". ==Civic life==