The world was shocked to learn that Taylor Swift and her longtime boyfriend Joe Alwyn have called it quits. The pair had been dating for six years.

However, what is still a mystery to fans — and curious minds alike — is what led to their split. A source close to the couple said that there were some differences that ultimately made their love story come to an end.

“They've had rough patches before and always worked things out, so friends thought they would take some time apart but eventually come back together,” the source told PEOPLE. They added that “ultimately” Swift and Alwyn “weren't the right fit for one another.”

The Midnights singer met the British actor back in 2017 and kept the relationship hush-hush often debunking engagement rumors.

“They had plenty in common and fell in love in a safe bubble while she was retreating from the world during Reputation,” adds the source, referring to Swift's 2017 studio album. “Then the pandemic hit, and they were locked down together and able to continue growing their relationship in this insulated way. But he didn't really ‘know' her yet outside of that bubble.”

A source told the publication that they bonded over art and music which proved to be a successful partnership as Swift released several songs that they created together. Alwyn wrote and co-produced with Swift under the pseudonym William Bowery. They worked together on six songs for Folklore, three songs on Evermore and “Sweet Nothing” on Midnights, her latest project.

Although the pair stayed together for six years, ultimately Swift's high-profile lifestyle got in the way of their relationship.

“Joe has struggled with Taylor's level of fame and the attention from the public,” says the source. “The differences in their personalities have also become harder to ignore after years together. They've grown apart.”

However, the insider explained that the two seemingly weren't in it for the long haul.

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“Taylor didn't see them working out in the long run,” says the source adding that the split happened “recently” and was “not dramatic.”

“They are friendly. She doesn't have anything bad to say about Joe,” adds the insider. “They just grew apart. Taylor is staying very focused on her tour right now.”

Swift's Eras Tour kicked off on March 17 and ends August 9. Neither reps for Swift nor Alwyn have commented on the couple's breakup.