While there are plenty of popular couples in the tennis world, none might be more popular in the United States than the relationship between Taylor Fritz and Morgan Riddle. Fritz (who withdrew from the Madrid Open that's taking place this weekend) is the world's No. 7-ranked player, according to the ATP , which makes him one of the sport's biggest names. But Riddle, who is a superstar on social media, is arguably an even bigger name than him at this point. Taylor Fritz and Morgan Riddle | IMAGO / ZUMA Press Wire These two have been together since 2020. They started dating around a year after Fritz finalized his divorce from professional tennis player Raquel Pedraza (which lasted from 2016 to 2019), with whom Fritz has a son named Jordan. Since then, both Fritz and Riddle's popularity has grown immensely. Fritz has become well-known in pop culture because of Riddle's prominence, and Riddle has become a major fashion influencer in the tennis space because she's almost always present at Fritz's matches.…