Calvin Harris reportedly refused to marry Taylor Swift.

Calvin Harris and Taylor Swift (c) Instagram

Calvin Harris and Taylor Swift (c) Instagram

It was initially believed the Scottish DJ was the one to call time on their 15-month relationship but it's now thought the "heartbroken" 26-year-old singer felt she had no choice but to walk away because he wasn't prepared to wed and have children in the foreseeable future.

A source explained: "Taylor ended things as she could feel their relationship wasn't heading in the right direction. She discovered they were on different paths in the last few weeks. It wasn't that they weren't happy, but when she raised the subject of their future it became clear they do not want the same thing at the same time.

"Taylor is heartbroken. But it could have been a lot worse if they were in this position in another 15 months. She always saw herself as a young mum. It's not that she's in a rush to settle down or anything. But she also doesn't want to waste time either."

And though Calvin "adored" the 'Bad Blood' hitmaker, who he was introduced to by mutual pal Ellie Goulding at the 2015 Brit Awards, his future plans didn't line up with hers and he didn't want the couple to live together yet.

The source told The Sun newspaper: "He was reluctant to make a complete commitment when his life is so crazy... He absolutely adored their time together, but being a devoted boyfriend is difficult to fit in with being the biggest DJ on the planet. He also loved having his own home in LA and didn't want to move in full time together. He loved his own space."

Although their romance has come crashing down, the 32-year-old hunk is adamant they will remain friends.

Taking to his Twitter account, he wrote: "The only truth here is that a relationship came to an end & what remains is a huge amount of love and respect (sic)."

However, the 'We Are Never Ever Getting Back Together' singer isn't hoping for a reconciliation.

A source said: "She was in Nashville with her family and they have been helping her through the break up.

"Taylor was really disappointed in Calvin and felt like he wasn't there for her. The relationship wasn't progressing the way she wanted it to.

"She felt like he wasn't taking it seriously enough and wouldn't come through for her when she needed him most. She felt down and like her needs weren't being met. She doesn't want to get back together."