The 42-year-old musician and Duhamel parted ways after eight years of marriage earlier this year.
"Honestly, it was just getting a little weird for us with all the romantic questions. We're great friends, we love each other so much, and it just got to the point where it was getting a little weird. There's no perfect time so we just decided to do it," Fergie told People magazine.
The singer is promoting her upcoming album, 'Double Dutchess', while her personal life has been making headlines.
"We just wanted to get adjusted in private. (And Axl's school has helped as) we have a co-op so Josh and I would walk there several times before the school season," she said.
The former couple recently confirmed their split the news in a joint statement.