I don’t mean to bring Taylor up again; I just know her ~public~ history well enough to recall it easily. Taylor and Calvin were honestly the golden couple in 2015. Taylor and Calvin seemed like the perfect pairing when they got together and were frequently seen out on romantic dinner dates, and even became Insta official. Just after they celebrated their one-year anniversary, Swift was seen dancing with Tom at the 2016 Met Gala. Taylor and Calvin were spotted by paps on a drive after looking pretty tense, which later lead to a breakup announcement. Soon after, Taylor and Tom were kissing in Rhode Island, in a series of pictures that shocked the Swiftie fandom. They embarked on a whirlwind summer tour, traveling to Rome, enjoying romantic lunches, and splashing in the ocean at Taylor’s 4th of July party. Things got messy when Calvin released a song that implied Taylor was unfaithful. Things got even worse when Taylor called Calvin out for not giving her credit on a song they co-wrote together called “This Is What You Came For.” Things got even more dramatic when Taylor’s 2017 album reputation came out and featured a little tune titled “Getaway Car” — which basically says Tom was her escape route from Calvin. Nowadays, everyone’s settled with their respective significant others, but boy was it a dramatic series of events. These lyrics summarize it perfectly, “While he was running after us, I was screaming, “Go, go, go!” / But with three of us, honey, it’s a sideshow / And a circus ain’t a love story / And now we’re both sorry.” 

Source: https://www.buzzfeed.com/amandaeedelman/13-famous-celeb-love-triangles-that-prove-relationships-are