Gwen Stefani blamed herself for her former husband Gavin Rossdale’s alleged affair with their nanny Mindy Mann, which reportedly caused “The Voice” coach to end the marriage. Even though she is currently believed to be dating Blake Shelton -- her co-worker from “The Voice," Stefani regrets hiring Mann and has been wondering if she could have done something to prevent the affair, Hollywood Life reported, citing a source.

“At first, Gwen blamed herself when she found out about Gavin and Mindy. She was full of regret that she somehow caused Gavin to have a wandering eye, that she could have somehow prevented the affair, that she never ever should have hired someone so young and cute,” the source told Hollywood Life, adding: “These thoughts tormented her for a long time. The could have, would have, should haves nearly destroyed her.”

The report added that there were signs of a budding affair between Rossdale and Mann dating as far back as 2012, when they took Stefani and Rossdale’s two sons Kingston, 9, Zuma, 7, hiking. A photo from 2012, carried by Hollywood Life, showed Rossdale’s hand on Mann’s rear while walking through the hiking route. Rossdale had reportedly claimed that he did that to save Mann from falling. The romance has allegedly been going on for three years.

Reports said that Stefani, whose divorce with Rossdale was revealed in August, found out about the affair in February after seeing suggestive text messages on an iPad between the two of them. The conversation also included a nude photograph of Mann and a plan to meet each other soon. "The iPad was linked to Gavin's phone," a family source told Us Weekly, adding: "One of the other nannies discovered the exchange and told Gwen."

Stefani and Shelton have been spotted together several times after their respective divorces, although Stefani denies being in a relationship with Shelton, who divorced Miranda Lambert in July. Stefani said that she learnt about the dating rumors from one of her sons.