According to gossip website Bitten and Bound, Marilyn, born Peter Robinson, has revealed that he was involved with Rossdale for five years before he married Stefani.
In 1995, Boy George's biography, "Take It Like a Man," had revealed that cross-dressing singer and the Bush frontman had been lovers in the 80s.
However, both Marilyn and Rossdale denied the claims.
But in an interview to In Touch magazine, Marilyn now tells that he agreed to deny their affair because of Rossdale's growing music career.
"He was just becoming successful in America. I agreed to lie against every grain in my body," the Daily Telegraph quoted him as saying.
"We were together five years, but it felt like forty.
Marilyn added Rossdale "was the love of my life." (ANI)