The world mourned with GENE WILDER when his wife GILDA RADNER died from ovarian cancer in 1989 – but his motivation for staying with her through the tragic ordeal wasn’t love — it was guilt!

That’s one of the shocking claims in the new bombshell book Gene Wilder: Funny and Sad, written by Brian Scott Mednick, which is due to go on sale later this month.

Mednick claims the actor was extremely unhappy in his marriage.

Still, Gene continued the ruse after Gilda died on May 20, 1989, co-founding cancer support groups in her name, and even telling Connie Chung during a 1990 interview that his last years with Gilda were "the best years of my life."

But Mednick writes: "With Gilda dead only a year, Gene knew it would be damaging to his reputation and the myth of them as an ideal couple to say anything less."

Then, 15 years after her death, Wilder began to confess that those were not the best years of his life, according to the book.

Despite their outward persona of being the perfect Hollywood couple, it was a one-sided relationship. Gilda’s love for Gene was intense and passionate. But Gene found her neediness suffocating, and he was unhappy for a long time, Mednick writes.

Gene knew he could never forgive himself if he left Gilda while she was fighting for her life with ovarian cancer, according to the book.

The Willy Wonka star and the Saturday Night Live comedian met in 1981 while filming Hanky Panky.

Although Gilda was married at the time, she divorced a year later and moved in with Gene. They wed in 1984.

In the few years before she was diagnosed with cancer, the book reveals that the couple struggled to have children.

The book says that Gilda thrived on being "Mrs. Gene Wilder" and her greatest dream was to have a baby with him. But she miscarried, and doctors blamed it on damage from an illegal abortion she had at age 19.

When Gilda first became sick, doctors diagnosed her symptoms as Epstein-Barr virus.But she knew something was very wrong, and repeatedly told doctors she was afraid she had cancer.

Eight months later, doctors discovered a grapefruit-size tumor and diagnosed her with ovarian cancer.

Although Gilda’s illness went into remission after aggressive treatment, it later came back with a vengeance. Gilda died in 1989 at age 42, and Gene remarried just two years later.

Gene and his wife Karen now live in the Connecticut home Gene once shared with Gilda.