American singer/songwriter Taylor Swift is reportedly not comfortable with Scottish singer/DJ Calvin Harris being in touch with his former girlfriends.

According to a report in Hollywood Life, the Red singer still carries scars from past relationships.

"She still has her own trust issues left over from other relationships, so the idea of him texting with his exes will be hard for her to take — she won't be happy about it," a source said.

"Calvin has given Taylor all the reason in the world to trust him. For one thing, he never hides his phone. It might sound small, but it's a big thing for Taylor because all her ex-boyfriends were major freaks about their phones. They'd never let her get near them. He's also so good about answering her calls and FaceTiming. She tests him and sometimes, she'll randomly FaceTime him and he always picks up — he's so transparent with her," the insider added.

It was previously revealed that Swift was single for a long time since splitting up with One Direction singer Harry Styles.

The Bad Blood hitmaker, who has a history of dating high-profile celebrities including Jake Gyllenhaal, Joe Jonas, Taylor Lautner, John Mayer, Zac Efron and Conor Kennedy, split with Styles last January, after dating for two months.

During an interview with Glamour UK magazine, the 25-year-old Shake It Off singer admitted that she does not find it easy having a boyfriend.

"There is no easy way for me to engage with romance. I'm really busy, so I can't. And it's a good thing that I feel really independent and I feel that my friends are all I need," she said.

"It's kind of a sad way I got there, though, being shamed into it. What else is it when you have two boyfriends in one year and everyone's calling you boy crazy, making jokes about you at awards shows? That's public humiliation. And I don't think its fair," Swift added.