Styles, 18, touched down at London's Heathrow Airport in his native Britain after a long flight from New York on Monday, Jan. 7. The boy bander kept things casual with an orange beanie and tan jacket, guitar in hand and shades tucked into his shirt.
His ex-girlfriend Swift, meanwhile, was snapped on a boat in St. Johns solo shortly after their split.
"They had a fight," an insider told Us Weekly of the short-lived romance, adding that Styles "said something he shouldn't have …This [breakup] is definitely going to be for good."
Last week, the pair went on an island getaway together to the British Virgin Islands. After their reported spat, however, Swift cut her trip short and returned home to Nashville to rehearse for her upcoming tour while Styles stayed on to soak in more rays and even visit Richard Branson's home.
Swift, 23, and Styles were first linked when they were spotted flirting on the set of The X Factor in mid-November. The pair then went on a series of very public dates -- including a happy trip to the Central Park Zoo and an all-night dance party after One Direction’s concert at Madison Square Garden in December.
Now, however, the pair are hardy speaking.
"They are 100 percent over," another source told Us, saying that Swift could be "intense" at times.