“This is not a revenge novel. It’s filled with joy, and when there are bad moments, it’s sort of how to keep going and learn not to let them pull you down,” said while discussing her new memoir, Uptown Girl, with fashion exec at the 92Y in NYC April 29. “And how to stay positive and maybe learn something from it.”

But the book’s contents are harrowing — especially when the supermodel opens up about her nearly decade-long marriage to , 76, then in the depths of alcoholism. The 71-year-old recalls giving the Piano Man chance after chance, only to have him come home wasted or disappear for days at a time.

On one terrifying occasion, a drunk Billy seemed to forget that he’d just consumed a pot of pasta and “went ballistic,” accusing his houseguests of stealing it. As he raged and the guests fled, Christie ran to protect their sleeping daughter, Alexa, now 39, ultimately fighting off her husband.

She writes, “Thank goodness, Billy, despite how drunk he may have been, knew that I was right: He wouldn’t want his little girl to see him like that.”