Kevin Federline is coming in swinging with more claims - this time about the grueling night he knew he wanted to fight for full custody of his and Britney Spears' kids. In his controversial new memoir You Thought You Knew, the former dancer reflected on an incident over 17 years ago which has "haunted" him ever since. You might recall that infamous January 2008 day when Britney locked herself in a bathroom with her youngest son Jayden James, now 19. At the time, he was just over a year old and Britney and Kevin were already divorced.