Britney Spears cracked up after learning ex-husband Jason Alexander had written a tell-all book on their relationship, The People can reveal. A source close to the singer said: “Jason had mentioned his plan to write a book on his time with Britney before. But she didn’t believe he would actually go through with it. Now she knows what’s in the book she is devastated. She never thought he’d discuss the sex they had together and her problem with drugs.” Read more.