AceShowbiz -

The reason why Calvin Harris dumped Taylor Swift may have been revealed. A friend of Taylor's told PEOPLE that he was "intimidated" by her success. "Taylor is an independent young woman, and she realizes it will take a very secure man to handle her success," the pal said.

Although there was "no drama," the friend revealed that "[Harris] said on multiple occasions that he was intimidated by Taylor, which is why he would not attend any events where she was being honored, or any award shows unless he was nominated."

Meanwhile, a source from Calvin's camp claimed the DJ ended his relationship with the "Blank Space" hitmaker because he didn't feel it was "leading anywhere." The source said, "They come from very different worlds. Taylor is used to being treated a certain way."

"It wasn't an equal relationship. Their age difference might not be significant for many couples, but for them it was part of the problem too," the insider continued. "Taylor somewhat lacks real-life experience. They will not be getting back together."

Despite their split, the DJ "very much admires her as a person and what she has been able to do with her career," the source said. "This is what drew him to her in the first place." The source added, "She works incredibly hard for things that she believes in. He always saw that as an amazing quality. They are still friendly."

Several days before the breakup news broke out, Calvin Harris and Taylor Swift were spotted together. They did look friendly, hugging each other before parting. E! News reported the split was "all done in a very mature fashion" although Taylor was "pretty upset." Their hectic schedules also played a part in their breakup.