Mr Cunliffe confirmed the split last night but said he wouldn't discuss it further "for the sake of our children and our wider family".
The couple have two young sons.
Karen Price is a prominent environment lawyer and at last year's election Mr Cunliffe reluctantly agreed to allow media into their Auckland home.
Campbell Live showed a glimpse of their home life in Herne Bay with her tending to her beehive, five chickens, a dog, a cat, budgies and canaries.
The pair met at Otago University and were married when she was 19 and he was 21.
Last year she told the Herald: "I thought he was pretty dishy.
"He was tall, country boyish, with a long blond afro and a washboard stomach."
But she also said she was a mother and lawyer before she was a political spouse.
She played a key role in his successful campaign in 2013 to become Labour leader in a run-off with Shane Jones and Grant Robertson.
After last year's election loss Karen Price set up a Twitter account under her nickname "@TarnBabe67" which anonymously attacked Mr Cunliffe's critics in caucus, such as Clayton Cosgrove.
Mr Cunliffe told Stuff at the time: "She's pretty awesome. [She] was defending her man, but nonetheless, she recognises it was ill-judged and at a time of huge stress."
By Audrey Young of the New Zealand Herald
