María Margarita's father is the well-known lawyer and owner of Banco BOD (BOD Bank) Víctor José Vargas Irausquín and wife Carmen Leonor Santaella Tellerías. She often appears in magazines around the world such as ¡Hola! from Spain that cover the life of the European royalty.
María Margarita married Luis Alfonso in a civil ceremony in Caracas on 5 November, 2004 and in a religious ceremony the following day at La Romana, Dominican Republic. The couple have a daughter, Doña Eugenia de Borbón y Vargas (b. 5 March, 2007 at Mount Sinai Hospital, Miami, Florida).
She has a sister María Victoria, married to Francisco Javier d'Agostino Casado. She also had a brother named Víctor José after his father, who died young.