Louise Redknapp says she still loves ex-husband Jamie but she began to feel “lonely” during their marriage.
The couple, who have two sons, divorced in 2017.
Singer Redknapp, 45, told Hello! magazine the former footballer is a “great dad”.
She said: “I still love him.
“After 21 years together how could I not still love him? He’s the father of my boys.
“Jamie’s a great dad and is very proud that our sons love me so much. He has old-fashioned values and tells them to respect and love their mum.”
The ex-Strictly Come Dancing contestant said she was “extremely happy” for “so much of my married life.”
But she added: “Bit by bit I began to unravel. I felt as if I was a spectator watching my life unfold.
“I was losing myself and felt very lonely. The lives of everyone around me were so fast-paced whereas mine felt stagnant.”
Despite the divorce, the pair “have a great system” of co-parenting, Redknapp said.
“Our rule is that while one of us is working, the other is with them.
“On Christmas Day we do the presents together, they’re from us both. Maybe this works now because neither of us is in a relationship, but I like to think it will always be like that.”
The full interview is in Hello! magazine, out now.