Rovell and Wilson met when she attended a Beach Boys concert at Pandora's Box, a Hollywood nightclub, in October 1962 with her sister Diane and their cousin Ginger Blake, who was dating Brian's then collaborator Gary Usher. Wilson and Rovell started conversation between sets and then began dating. Wilson was 20 years old, while Rovell was a 14-year-old high school student.
Wilson became the producer of the Honeys, a girl group consisting of Marilyn, Diane and Ginger. Wilson and Marilyn married on December 7, 1964, as the Honeys' career was declining. Wilson then began exhibiting symptoms of schizoaffective disorder. The couple had two daughters, Carnie and Wendy.
In 1971, Marilyn and Diane formed the band Spring (later renamed American Spring) and together they recorded a few singles and an album. In 1974, due to Brian's growing seclusion from the outside world, following his father's death, Marilyn temporarily stopped her music career. In 1976, Marilyn persuaded Brian to begin psychotherapy by pretending to go herself and returning home happy, in contrast to Brian's dark moods. He recovered somewhat, but after his family and members of the Beach Boys insisted he cease therapy and return to making music full-time, Wilson's mental health worsened.
Marilyn and Brian amicably divorced in 1979. In a Rolling Stone magazine in the early 1990s, Marilyn recounted that Brian's increasingly erratic behavior was affecting their two daughters, and that she told him, "I love you, but the girls have got to have a normal home life". She also recalled that she told the girls that their father was "a genius", but also mentally ill. Brian was likewise supportive of Marilyn, and though estranged from the girls during his recovery, was finally able to connect with them as adults.