What Britney Spears is really like behind closed doors: For first time, Kevin Federline reveals secrets he refused to spill even for $1 million... including 'terrifying' acts that left their children running to him ⊕

Federline has published an avalanche of explosive claims about his ex-wife Spears in his new tell-all memoir, You Thought You Knew. Now, in an exclusive interview, he's revealing even more...