Kelly Clarkson and ex-husband Brandon Blackstock "changed their perspectives" on life after their bitter divorce during his three-year cancer battle. "Co-parenting was not easy for Kelly because she was the one who had to transport the kids, so it was really her life that was always turned upside down," a source exclusively told Us Weekly on Friday, August 8, adding that Blackstock's health diagnosis didn't necessarily bring the former couple "closer together" but instead "changed their perspectives." "She is their [children's] primary parent.