This, despite their harsh words for each other in public since they broke off their engagement in March 2009, and a custody fight over their son, Tripp, now almost 18 months old. The source says things have re-heated between Bristol, 19, and Levi, 20, now that Bristol's mother, former GOP vice presidential candidate and ex-Alaska Gov. Sarah Palin is on the road a lot, and Bristol has her own place. "They spend more time together than most people think." The course adds, "Levi even stays overnight. I even think they are back together."