The 64-year-old dance star and her 51-year-old actor partner are said to have called it quits three years after getting engaged.
This news follows Ballas's recent revelation that she had put their engagement plans on hold, though at the time, she confirmed they were still a couple.
The pair first met in 2018 during a pantomime production of Jack and the Beanstalk and have since faced the challenges of a long-distance relationship, with Ballas based in London and Taylor in Liverpool.
Their busy schedules and the distance between them are believed to have played a role in the split.
A source told The Sun: "As with any break-up, it is, of course, a very sad situation. She gave her all to that relationship and in the end came to the realisation that it wasn't going anywhere.
"She gave her all to that relationship and in the end came to the realisation that it wasn't going anywhere.
"She made a lot of effort to see Danny and support his theatre and panto work, travelling up and down the country.
"Distance also played its part - Shirley lives in London with her mother and Danny remains based in Liverpool; that commute is a killer."
Despite the breakup, sources highlight Ballas's resilience: "Shirley is a strong, resilient character and is looking better than ever. She will 100% bounce back - 2025 promises to be an absolute corker for her."
The Standard has contacted Ballas's rep for comment.
The couple's split seems to be on friendly terms, as they still follow each other on social media.
In a 2021 interview with Prima magazine, Ballas shared that her relationship had "changed my life," describing her partner as "kind and very caring -- he's always there for me."
She even hoped he'd propose someday, adding, "Come on, Danny!" as she playfully encouraged him. However, earlier this year, Ballas revealed she had reconsidered marriage, saying she'd "changed her mind" about walking down the aisle again.
The BBC star shared: "I just feel that at this particular point in my life, my mother and I have got this great relationship and we want to do some travelling."
Ballas has been married twice before: first to Sammy Stopford from 1980 to 1984, and later to Corky Ballas from 1985 until 2007.