The singer recently cast doubt on the future of the group following the reunion of the band's original members, Keisha Buchanan, Mutya Buena and Siobhan Donaghy, who have returned under the name Mutya Keisha Siobhan.
However, she has now come clean about the real status of the current line-up, which also includes Heidi Range and Amelle Berrabah, insisting they have not worked together in two years and have no plans to reunite.
She tells Digitalspy.co.uk, "This is a tricky one because I don't feel comfortable lying, saying we're in the studio recording and we're going to bring music out next year, which seems to be the favoured line. I think it's unfair to fans and we should be honest.
"The band being over is definitely not my choice. I kind of was unlucky in that I came in (to Sugababes) towards the end of the cycle when things naturally came to the end.
"There was so much drama surrounding the group, I think the music just got lost. I don't like all the drama and the negativity. We kind of fizzled out about two years ago."
She also blames the constant line-up changes for bringing about the group's demise, and hints that she will tell the real story of the Sugababes in a future book, adding, "One day I'm hoping that I'll be able to put out a book and explain that whole chapter."
The band's original line-up broke down in 2001 when Donaghy left. She was followed by Mutya Buena in 2005 and Buchanan in 2007, while the band continued performing with a new line-up. Ewen joined Sugababes in 2009 to replace Buchanan.