Sir Paul McCartney's estranged wife Heather Mills phoned the ex-girlfriend of her personal trainer BEN AMIGONI, to reassure her the pair were not having a relationship. JO BRADFORD, 23, says her relationship with Amigoni, 22, began to fall apart when he began working for the former model last year (05). Bradford says, "Heather stole my thunder. I suddenly felt our life wasn't good enough for him. We'd never had an argument before he went to work for her." Bradford claims MCCartney even phoned Amigoni one day to ask him if he was having an affair with Mills, before their respective splits. After Mills announced her marriage split in May (06), she asked Amigoni to be her exclusive personal trainers, based at her Sussex, England estate. Bradford explains, "He said it was too big a career move to miss. I was uneasy and was proved right. "He became obsessed. He even read her autobiography." Amigoni ended his three-year relationship with Bradford in a handwritten note in September (06) and weeks later she received a phonecall from Mills. Bradford adds, "I had always wondered if she and Ben were having an affair. Ben always denied it. "I don't know why she had to reassure me of anything. She was only interested in herself - and making sure I didn't speak out."