Britney Spears is responding to her ex-husband Kevin Federline's allegations against her in his upcoming memoir, which include that she watched her sons sleep "with a knife in her hand." "With news from Kevin's book breaking, once again he and others are profiting off her and sadly it comes after child support has ended with Kevin," a representative for Spears, 43, told Entertainment Weekly in response to excerpts released from Federline's upcoming memoir, You Thought You Knew."All she cares about are her kids, Sean Preston and Jayden James, and their well-being during this sensationalism.