Read Excerpt: 'Madoff's Other Secret: Love, Money, Bernie and Me'

Aug. 25, 2009— -- While Bernard Madoff was cheating thousands of investors out of millions, he was also allegedly cheating on his wife, according to Sheryl Weinstein, who claims to have been Madoff's mistress.

Weinstein is speaking to "Good Morning America" for the first time about her romantic relationship with the disgraced and now jailed financier and the book she wrote on the affair, "Madoff's Other Secret: Love, Money, Bernie and Me."

Read an excerpt of the book below, and head to the "GMA" Library for more good reads.

It was nine a.m. on February 25, 1988, when I stepped out of the cab in front of the red-enameled granite and steel building at 885 Third Avenue and pushed my way into the glistening, glass-enclosed lobby. It was New York's famed Lipstick Building, the name given to the thirty-four-story East Side skyscraper that stretches between Fifty-third and Fifty-fourth Streets.

Since its completion two years earlier, the three-tiered, ultra-modern structure had drawn many admirers. They viewed its curves and jazzy red hue as a welcome contrast to the black and white, sharp-edged design of its neighbor, the Citicorp Center. Lipstick Building designers John Burgee and Philip Johnson were being hailed for the building's sleek, elliptical lines and its unusual egg-shaped lobby. The lobby soared two stories high and incorporated a pedestrian walkway. The structure was so fanciful and pleasing, it would have been hard to imagine that anything so apocalyptic could be percolating within its walls.

I was curious to check it out for myself and set off toward the bank of elevators in the lobby. The much-touted Toscana Restaurant occupied a large chunk on the Fifty-fourth Street side. I would just take a quick peek inside, not wanting to be late for my 9:15 meeting with the principal of the brokerage house that bore his name.

As chief financial officer of Hadassah, the Jewish charitable organization of 350,000-plus women, I'd been asked to accompany three of our executive volunteers to a meeting to discuss the logistics of a donation. It wasn't part of my typical agenda, but this was no ordinary transaction.