Taylor Swift and Joe Alwyn have reached the end of their love story.

The couple broke up a few weeks ago after six years of dating, and a source close to the Grammy winner and the Conversations with Friends actor tells PEOPLE the split was largely caused by "differences in their personalities."

"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," says the source, noting that "ultimately" Swift, 33, and Alwyn, 32, "weren't the right fit for one another."

Reps for Swift and Alwyn have not commented on the breakup.

The "Lavender Haze" musician was first publicly linked to the British actor in May 2017, when it was revealed that the pair had been quietly dating for months. Though it's not clear exactly when they met, fans have speculated that Swift and Alwyn first crossed paths at the 2016 Met Gala.

"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."

Throughout their relationship, the pair kept details of their romance to themselves, demurring on engagement rumors in recent years.

Sources say the pair bonded quickly over shared passions for art and creativity. Indeed, Swift has released 10 songs co-written and/or co-produced with Alwyn, who wrote under the pseudonym William Bowery. The collaborations include six songs on Folklore, three songs on Evermore and "Sweet Nothing" on Midnights.

Still, insiders say the actor — who emphasized his need for privacy when asked about Swift during interviews — didn't like the limelight.

"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."

According to multiple sources, Swift and Alwyn had been "talking about marriage as recently as a few months ago."

But at the end of the day, the couple wasn't ready for a future together. "Taylor didn't see them working out in the long run," says the insider, who adds 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."

Despite the breakup, the source adds, "There is a lot of respect still between them."

Swift is currently performing shows throughout North America on The Eras Tour. A week before news broke of her split from Alwyn, she surprised the audience by swapping out Folklore track "Invisible String," which focuses on two soulmates, with "The 1," a song that instead centers around a lost love and remembering what was once had.

Following her three latest concerts in Arlington, Texas earlier this month, Swift was spotted shooting a music video late last week in Liverpool, England. Her next shows are on April 13, 14 and 15 in Tampa, Florida.