#RelationshipGoals wasn't even a thing when they dated in the early 2000s – but that's probably not the hashtag we'd use to describe Carter's 2014 attempt to woo back his former teenage sweetheart on Twitter. "Him reaching out through social media? It's ridiculous," Duff shot back in a March 2015 Cosmopolitan interview. It's time to stop living in the past: "Keep it between text messages," she added.