"He's super chill and very quiet. He just doesn't like the hoopla," says an industry insider about Harris' introverted personality

Credit: Courtesy Taylor Swift

It wasn’t cheating or any juicy drama that caused Taylor Swift and Calvin Harris’ romance to end, but the stars’ differing personalities were a big contributing factor to their split, multiple sources tell PEOPLE.

Before dating Harris, 32, the “Shake It Off” singer, 26, built up a strong group of female friends – including Selena Gomez, Karlie Kloss, Serayah and more – whom she has credited for consistently having her back.

“My friendship group is one of my favorite things about my life right now,” she told Vogue Australia in 2015. “It’s the first time in my life that I’ve had anything strong like that in the friendship department.”

Unfortunately, Swift’s more outgoing personality and large circle of friends clashed with Harris’s introverted personality, says one industry insider.

“He’s super chill and very quiet,” says the insider. “He just doesn’t like the hoopla with the squad and all of that. He doesn’t like to have cameras in his face all the time. He’s a private guy.”

A Swift friend also previously told PEOPLE Harris was intimidated by the singer’s success and refused to accompany her to shows for which he wasn’t up for an award, but a source close to the DJ says that “couldn’t be further from the truth.” Adds the source: “He has global success. Why would he be intimidated by anyone?”

Though the pair ultimately didn’t work out, the Harris pal insists he and the singer – whom the Swift pal says “is an independent young woman” who “realizes it will take a very secure man to handle her success” – will remain on good terms.

“He very much admires her as a person and what she has been able to do with her career. This is what drew him to her in the first place,” says the Harris pal. “They are still friendly.”