Article continues below advertisementBritney Spears' ex-husband Kevin Federline made countless jaw-dropping accusations against the singer in his new memoir, You Thought You Knew.In excerpts leaked before it's Tuesday, October 21, release, the former backup dancer alleged that the pop star mistreated their sons, Sean Preston, 20, and Jayden James Federline, 19, for years.Article continues below advertisementKevin Federline Accuses Britney Spears of Being ViolentSource: @britneyspears/instagramKevin Federline claimed ex Britney Spears was violent with their eldest son and babied their youngest.