Everything We Know About Calvin Harris and Taylor Swift's Breakup – So Far

Since sources confirmed to PEOPLE on Wednesday that Calvin Harris and Taylor Swift broke up after 15 months of dating, more details have emerged about the split.

Here's what we know so far:

No one cheated.

As far as breakups go, this one was pretty clean. "There was no drama. Things just don't work out sometimes," an insider told PEOPLE. "No one cheated.

Harris was 'intimidated' by Swift's success.

A friend of Swift's tells PEOPLE that Harris ended the relationship because he couldn't deal with all of her success. "[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," the friend says. (For example: He didn't attend the Met Gala, which Swift co-chaired last month, or the Grammys in February.) "Taylor is an independent young woman, and she realizes it will take a very secure man to handle her success."

The split was not surprising to Swift.

A source close to the DJ – whom sources confirm ultimately pulled the plug on the relationship – tells PEOPLE that the split "wasn't a shock" for Swift because the couple had ongoing issues. "They come from very different worlds," the source says. "Taylor is used to being treated a certain way."

Their age difference was part of the problem.

The source also adds that 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," says the Harris source. "Taylor somewhat lacks real-life experience. They will not be getting back together."

They are still on good terms.

The insider tells PEOPLE that Harris still "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 … She works incredibly hard for the things that she believes in. He always saw that as an amazing quality. They are still friendly."

Swift spent time with her family before the news broke.

Swift went home to Nashville, Tennessee, before her split was announced. On May 20, the singer posted a video to her Instagram in which she and her mom, Andrea Swift, enjoyed some mother-daughter bonding time, grilling outside while a frog croaked nearby.

Their differing personalities played a part.

One industry insider says that Swift's more outgoing personality and large circle of friends (a.k.a. her squad) clashed with Harris' introverted personality. "He's super chill and very quiet," the source told PEOPLE. "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."

They still have love and respect for each other.

Harris spoke out on Thursday night about the split. "The only truth here is that a relationship came to an end & what remains is a huge amount of love and respect," he wrote on his Twitter account. (Swift retweeted it.)