«Treacly,» «boring» and «sexless» aren’t words you’d typically ascribe to one of the world’s biggest pop stars. But they’re adjectives that journalists and festival organizers have lobbed at Ed Sheeran, who rock icon Morissey slammed in 2015, telling Boulder Weekly that «things can’t possibly get any worse» than his music. Yet despite the vitriol, the scruffy British troubadour has achieved perhaps inexplicable success. His first two albums — 2012’s + (read as «plus») and 2014’s x (read as «multiply») —…