BARBARA: Katy Perry had been having doubts about her relationship with John Mayer ‘’for some time’’ before they split. The ‘Dark Horse’ singer reportedly called time on her 18-month romance with the ‘Gravity’ hitmaker last week but an insider says the decision had been a long time coming. The source told E! News that Katy felt there were ‘’certain differences in their personalities’’ and she felt she and John were ‘’not right for each other’’ but she took some time to ‘’acknowledge’’ her instincts and end the relationship. Katy is said to be ‘’relieved’’ the romance is over and is ready to move on with her life.–EXPO