Jessica Simpson seem very happy after her split from John Mayer, according to her friends. The singer and actress celebrated her new-found freedom recently with friends in Los Angeles. A source told Us Weekly magazine, "She was telling friends, 'We were so different, we were fighting so much. I'M really happy to be out of that relationship. This time, it's totally done.'" Another source close to the star confirms that Simpson is officially single. Jessica, 26, and singer John, 29, enjoyed a nine-month romance before breaking up last month.