Rita Ora on Calvin Harris: "I Thought He Had My Back"

Courtesy Beau Grealy/Marie Claire

If Calvin Harris proposes a duet with Taylor Swift , she might want to think twice.

According to Rita Ora, who dated the world's highest-paid DJ and producer for 13 months, working with Harris may have led to their June 2014 split.

"There was a reason why I split up with him. And there was a reason why I'm at this point in my life where I feel like I have so much musical freedom, and I don't have to explain myself to anybody," the singer says in Marie Claire's July issue, on newsstands June 23. "It was more of a thing where I was in awe. I was at that point in my relationship where I felt he could do no wrong. I thought he had my back and that he'd never steer me wrong. But then 'I Will Never Let You Down' came out, and everything started to go a bit weird. I don't know if it was because business was mixed with personal or what."

Ora was supposed to sing at the Teen Choice Awards in August 2014, but she was forced to cancel after Harris refused to allow her to perform their single. Harris explained himself on Twitter, writing, "You'll only know 1 side of the story RE Teen choice awards because I choose not to talk to the papers about every aspect of my personal life. But just know I had a damn good reason." Ora shared her side of the story, telling On Air With Ryan Seacrest, "For anybody who doesn't understand how it works, he wrote and produced the song. So he has to approve anything TV-wise for anybody who doesn't get it. And obviously he owns the rights to it and he didn't approve the Teen Choice Awards...It is what it is, man."

The shock and heartbreak didn't go diminish overnight.

Three months post-split, Ora told Glamour U.K., "I'm gonna tell you the truth: I'm not doing too great. But, I'm doing better than I thought. I adore him and he's such an amazing human being. It was more about the situation. It was inconvenient. It sucks. It wasn't about 'us.' It was about the world we live in."

Courtesy Beau Grealy/Marie Claire

When she covered Cosmopolitan in December, the "Poison" singer revealed she was feeling much better. "It was the right guy at the wrong time," she said of Harris, who rebounded with Aarika Wolf. "I was about to start a tour, and he was also all over the place." Ora, who had been linked to Ricky Hill, continued, "There's only so much you can do when you don't see each other. I really admire people who have long-distance relationships. It's an incredible achievement. I couldn't do it."

What has Ora learned in the year since she split with Harris?

"I'm afraid of being alone," the singer, 24, tells Marie Claire. "I'm not afraid to admit that, you know. I'm not embarrassed to admit that. I just hope it's not a never-ending cycle. Sometimes love just makes you feel crazy. And that feeling that we have as girls, just to have that feeling, even for five seconds, it's like crack. I mean, don't compare it to that, but you know what I mean. It's like comfort eating."