Gisele Bündchen allegedly begged Tom Brady for more help with their kids and attention to their family in a “serious” handwritten note ahead of their bombshell divorce. The supermodel gave the retired NFL star the letter after the 2018 Super Bowl, when the New England Patriots lost to the Philadelphia Eagles, according to a new book “Brady: An American Story and the Price of Greatness.” “She explained that their marriage wasn’t working,” Author Lars Anderson writes in an excerpt posted by Daily Mail Friday. “She needed more of him, more of his time, more of his attention, more of his heart.” Anderson, who details the exes’ relationship…