It’s no longer surprising for memoirs by music stars and celebrities to contain some major disclosures, be it Mariah Carey confessing to an extramarital affair with baseball great Derek Jeter or Carlos Santana revealing that he was subjected to sexual abuse as a child. Native San Diego singer-songwriter Stephen Bishop also makes a major disclosure in his new autobiography, “On and Off,” which takes its title from his lilting 1977 hit, “On and On.” But Bishop — whose songs have been recorded by Art Garfunkel, Barbra Streisand, The Four Tops, and dozens more — takes his time before dropping a so…
