Musicians marry musicians---or at least members of other musical families- with considerable frequency. Here is a list of some of the better-known musical marriages, many (though not all) of which proved to be permanent:

HUSBAND-WIFE

Wolfgang Amadeus Mozart,composer - Constanze Weber, a cousin of Carl  Maria von Weber
Georges Bizet, composer - Genevieve Halevy, daughter of Fromental Halevy
Robert Schumann, composer - Clara Wieck, pianist
Charles de Beriot, violinist - Maria Malibran, contralto
Richard Wagner, composer - Cosima von Bulow, daughter of Franz Liszt, wife of Hans von Bulow
Richard Strauss, composer - Pauline de Ahna, soprano
Arnold Rose', violinist - Justine Mahler, sister of Gustav Mahler
Engene d'Albert, composer and pianist  - Theresa Carreno, pianist, was his first  wife; 5 others followed
Arnold Schoenberg, composer - Mathilde von Zemlinsky, sister of Alexander von Zemlinsky; following her death, married Gertrud Kolisch, sister of Rudolf Kolisch
Josef Suk, violinist Otilie - Dvorak, daughter of Antonin Dvorak
Leopold Stokowski, conductor - Olga Samaroff, pianist-first of his 3 wives
Pierre Luboshutz, duo-pianist - Genia Nemenoff, duo-pianistist
Efrem Zimbalist, violinist - Alma Gluck, soprano
Eugene Ormandy, conducor - Stephanie Goldner, harpisttor
Wilfred Pelletier, conductor - Rose Bampton, soprano
Robert Casadesus, pianist - Gaby Casadesus, pianist
Kurt Weill, composer - Lotte Lenya, singer
Xavier Cugat, band leader - Carmen Castillo, Lorraine Allen, and  Abbe Lane, all singers
Andre Kostelanetz, conductor - Lilly Pons, soprano
Jan Kiepura, tenor - Martha Eggerth, soprano
Rudolf Serkin, pianist - Irene Busch, daughter of Adolf Busch
Vladimir Horowitz, pianist - Wanda Toscanini, daughter of Arturo Toscanini
Eugene Istomin, pianist - Martita Casals, widow of Pablo Casals
James McCracken, tenor - Sandra Warfield, soprano
Mstislav Rostropovich, cellist and conductor - Galina Vishnevskaya, soprano
Thomas Stewart, baritone - Evelyn Lear, soprano
Richard Bonynge, conductor - Joan Sutherland, soprano
Henry Lewis, conductor - Marilyn Horne, mezzo-soprano
Daniel Barenboim, pianist - Jacqueline du Pre', cellist and conductor
Pinchas Zukerman, violinist - Eugenia Zukerman, flutist and conductor