The singer appeared on the BBC competition series in 2016, where she reached the final with professional dancer Kevin Clifton.
The following year, Louise announced her split from footballer Jamie Redknapp, who she had been married to for 19 years.
Writing in her new autobiography You’ve Got This: And Other Things I Wish I Had Known, Louise said that she would have been “too scared” to leave her marriage had Strictly not set her on a “new path”.
“If I’d done the show four years earlier, this wouldn’t have happened. I wouldn’t have walked away from my marriage,” she wrote. “[It] simply wasn’t worth putting anyone I loved or love through the heartache.”
Louise continued: “I still wish I’d done things differently because I feel like I hurt a lot of people and I’ll always be sorry for that.
“I felt like certain people had my back, and, in hindsight this wasn’t really the case. I was so scared about going back to normal life and losing what I’d achieved on the show.”
In February, Louise admitted that she had suicidal thoughts following her split from Jamie.