The 41-year-old mum of two and ex-Saturdays star is releasing a song called Walk Away on Thursday.
It comes weeks after she ditched her relationship with Haye and his girlfriend Sian Osborne, denying they were a “throuple” as she was not dating Sian.
Last week, Una sensationally claimed she was tricked into entering the throuple.
Una confirmed she shared her ex with another woman, but said she was “hoodwinked” into being in a throuple, and left the relationship as soon as she realised.
And on her decision to speak out about it, she admitted: “I feel relieved I’ve got to say my bit.
“The truth from the horse’s mouth.”
Una addressed her experience on Vogue Williams and Joanne McNally’ podcast, My Therapist Ghosted Me, and she explained she met David through a dating app.
She shared: “Dating HIM is the right term because that’s how it was, it wasn’t a throuple. We had a lovely relationship.
“It was casual, it wasn’t serious. I was happy enough with it. It was in a romantic capacity.
“He was very honest that I wasn’t the only woman he was seeing, I was very aware he was seeing other people. I knew he was being honest and it’s not like I was being cheated on.
“I knew he wasn’t husband material, just a bit of fun and I was enjoying it.”