Watch: Britney Spears' Ex-Husband Jason Alexander Shares Fiery Message About Kevin Federline's BookJason Alexander isn't buying Kevin Federline's story. Britney Spears' longtime friend and first husband is speaking out amid claims included in Kevin's forthcoming book You Thought You Knew, noting he "can't stay silent." "It's easy to point fingers now, to talk about Britney's struggles like you were just some innocent bystander watching it all happen," Jason wrote in an Oct. 15 Instagram post set to Jelly Roll and Post Malone's 'Losers.'" "But that's not what went down. You were her husband.