Kevin Federline has reportedly splashed out $14,000 decorating his two sons nurseries. Kevin - the estranged husband of Britney Spears - has just moved into a $3.2 million Californian mansion and has been busy giving it his own stamp. Kevin was determined for his and Britney's children, 22-month-old Sean Preston, and 10-month-old Jayden James, to have luxurious rooms and spent a small fortune at exclusive Los Angeles boutique Petit Tresor.When Sean Preston was born in September 2005, Britney splashed out $45,000 on his nursery in the Malibu mansion she and Kevin used to share.The separated couple, who split last November, are currently involved in a bitter custody battle over their two children. Last month, it was alleged Kevin had said 25-year-old Britney - who recently spent time in rehab to be treated for alcoholism and alleged post-natal depression - was too young and mentally unstable to be a mother. A source told Us Weekly magazine: "He thinks she's mentally unstable and too young to be a mom. He expects to have full custody of his children one day."But he loves his kids and, to that extent, he will look after Britney."Kevin, 28, also has two children, Kori and Kaleb, from his relationship with actress Shar Jackson.