Late rocker Warren Zevon's ex-wife has revealed the Werewolves of London hitmaker had returned to his heavy-drinking, drug-taking ways before his death in 2003 in a new memoir. Crystal Zevon, who was married to the rock star from 1974 to 1979, admits her late husband's death was tough on the family because he turned his back on 17 years of sobriety in a bid to cope with the fact he was losing his cancer battle. She recalls the painful end of Zevon's life in new book I'll Sleep When I'm Dead: The Dirty Life + Times of Warren Zevon. Crystal says, "It was very painful because we lost that time with him." But the ex-wife admits Zevon did sober up just before his death after the birth of his great-grandchildren: "He looked at the relationships in his life... He was really there and present." Zevon's ex-wife admits the book took her a long time to write because painful memories of her life with Zevon, who she says could be "cruel for cruelty's sake," made her consider quitting the project. She tells the Los Angeles Times newspaper, "There were many times where I said, `I can't do this, I don't want to read another word, let alone put us all out for public consumption.' "Then I'd run across some great line of the moment when a song trigger came to him, and I'd say, `The story has got to be told...' I fell in and out of love a lot of times."