Singer Joe Jonas and Sophie Turner had 'been living separate lives for months before the singer filed for divorce following four-year marriage

American singer-songwriter, Joe Jonas and Sophie Turner had ‘been living separate lives for months’ before he filed for divorce.

The Jonas Brothers singer filed for divorce on Tuesday, September 5, to end his marriage after four years.

'They were not separated but they've been living separate lives for months,' an insider familiar with the celeb couple told People of Jonas, 34, and Turner, 27.

The Jonas Brothers singer and the Emmy-nominated Game of Thrones actress had been apart 'the whole summer,' the source said, adding that people close to the couple weren't surprised by the split.

This Is Me singer - who remained wearing a wedding band while hiring an attorney for the split - hasn't 'gotten along in a while' with Turner, the source told the outlet.
 

Amid the hostility, the source said that Turner and Jonas are 'hoping to resolve this all amicably.'

Turner and Jonas are parents to two young daughters, three-year-old Willa, and a one-year-old identified in legal docs as D.

The source told the outlet that while the couple did have a prenuptial agreement in place, it was not immediately clear how the stars would divide their time with their kids.

As far as custody goes, this literally all just happened, so they're figuring it out in real-time,' the insider said. 'As a family, they were based in Florida.

'The kids were with him the last few months, traveling with him with family while he's been on tour. Sophie's been working in the U.K.'

Turner has been pictured in England working on the forthcoming ITVX drama Joan, which is a limited series about Joan Hannington, who masterminded a number of jewel heists in the 1980s.

According to a synopsis from producers, the series is focused on the story of 'a woman who goes between her thriving and daring career as a jewel thief, all whilst trying to get her daughter back from social services.'

Hannington is described as 'a mother in despair swept up in the exhilarating world of crime.'

The Turner-fronted limited series co-stars Frank Dillane, Laura Aikman, Kirsty J. Curtis, Gershwyn Eustache Jnr, and Tomi May.

In regards to the split, an insider told Page Six Tuesday that Jonas made a last-ditch effort to 'salvage' the marriage before moving forward with his 'last resort' of filing for divorce. 

Turner and Jonas 'were going through it this year' according to a source who spoke with Page Six, following reports that Turner's alleged 'partying' caused a rift in the marriage.

'Divorce was a last resort for Joe. He never wanted to break up his family, but he had to take what he felt was the best course of action for his girls,' the insider added.

The pair, who reportedly have an ironclad prenup, share a three-year-old daughter Willa, and a one-year-old daughter, whose name they have not revealed, but who was listed as D.J. in the divorce filing.

The source went on: 'An unhappy home isn't a home, and the truth is that he and Sophie were going through it this year. There's a lot of noise out there, but it wasn't a straw-that-broke-the-camel's-back situation like it's being reported.'

'It just kept building, and Joe finally reached a point where he felt that he had exhausted all options to salvage the marriage.'

It comes after reports that Sophie's lifestyle is what caused her estranged husband to file for divorce.

The actress allegedly 'likes to party', which caused a clash with the musician, who is more of a homebody. 

'She likes to party; he likes to stay at home. They have very different lifestyles,' a source revealed to TMZ.