John Mayer's ex, Minka Kelly, has some pretty interesting insight into John's new relationship with Jennifer Aniston. Minka received a call from John prior to the story breaking about his relationship with Jennifer. He apologized to Minka, 'Sorry, but I'm really in love,'" Minka's pal tells Page Six. Minka found that pretty intriguing, considering the fact that "during his relationship with her, John mentioned, 'I don't really get this Jennifer Aniston thing.'" Innnnnteresting…