Former First Lady Jacqueline Kennedy advised her sister-in-law, Joan, to stop being a doormat for her philandering hubby, Ted Kennedy - and if he didn’t shape up, to move out, according to letters up for auction tomorrow in Connecticut. “This is the 20th century - not the 19th - where the little woman stayed home on a pedestal with the kids and her rosary,” Jackie wrote in an undated four-page note to the senator’s wife and miserable mother of three. “Your life matters - as much as him - you love him - but you can’t destroy yourself.” The hand-written...