The singer appeared on the BBC ballroom show in 2016, with Louise and husband Jamie Redknapp announcing their separation the following year.
Writing in her autobiography, You’ve Got This, Louise said taking part in Strictly “wasn’t worth” the heartache it subsequently put her loved ones through.
She wrote: “If I’d done the show four years earlier, this wouldn’t have happened. I wouldn’t have walked away from my marriage.”
She added that starring on Strictly “simply wasn’t worth putting anyone I loved or love through the heartache”.
Louise, who was partnered with pro dancer Kevin Clifton, did acknowledge that the show gave her a “new path” and showed she “could find work again”, but said: “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.”
Louise and Jamie were married for almost 20 years prior to announcing their split, and are parents to sons Charlie, 16, and Beau, 12.
Since her split from Jamie, Louise appeared as the lead in a touring production of Cabaret and in the West End show 9 To 5, as well as releasing her first album in almost two decades, Heavy Love.
Last year, Louise said she felt “invisible” and “less of a person” towards the end of her marriage, but insisted she still “adores” her ex-husband.