Shawn Mendes and Camila Cabello have a “really honest relationship”. The 23-year-old pop star and Camila, 25, announced their break-up in November, but they’ve subsequently remained good friends and Shawn even gave his ex-girlfriend a preview of his new single, ‘When You’re Gone’, months before its release. He told ‘Daily Pop’: “Camila heard this song months ago, so we have a really honest relationship. I would never really put a song out about her before she would hear it.” Shawn and Camila both accept that heartbreak is a big inspiration for musicians. And the former Fifth Harmony star is su…