Singer Taylor Swift and DJ Calvin Harris have ended their 15-month relationship, according to reports.An insider told People magazine: ‘There was no drama. Things just don’t work out sometimes.’The news comes after the Scottish DJ was pictured looking downcast, as he jetted home to Los Angeles on Tuesday following a brief trip to London.They were ranked last year as the music industry’s highest-paid celebrity couple by Forbes, with combined earnings of more than $146 million.