Britney Spears' recent behaviour is the result of the pop superstar's fears of losing her kids to estranged husband Kevin Federline, according to her ex-boyfriend ISAAC COHEN. The singer and mother-of-two stunned fans and paparazzi photographers when she tearfully cut all her hair off in a Los Angeles salon on Friday (16FEB07), before having two tattoos etched on her chest. But Cohen, who briefly dated the TOXIC singer earlier this year (07), insists her wayward behaviour stems from the fear of losing her two baby sons, Sean Preston and five-month old JAYDEN JAMES, following her split with Federline last year (06). He says, "Britney's boys mean everything to her and she worried she might lose them in a custody battle. It was clear she was not over her marriage. "She'd lie like a rag doll in my arms and say, "Why can't everyone leave me alone?'"