Nick and Kathryn Greiner pictured in 2003. The Greiners have announced they are separating.
Former NSW premier Nick Greiner and his wife, Kathryn, have agreed to separate after more than four decades of marriage.
A spokesman for the pair said on Monday: "Nick and Kathryn Greiner have agreed to separate. After a great deal of thought they have decided to lead individual lives.
"The decision is mutual and amicable. They remain good friends and are completely devoted to their family. They will not be making any further comment."
Mr Greiner, the premier and treasurer of NSW between 1988 and 1992, married Kathryn Callaghan in 1970. The couple separated for a year in the mid-1990s after Mr Greiner admitted having an extra-marital affair.
At the time, Mrs Greiner was running for Sydney lord mayor. She went on to serve as a Liberal-aligned independent councillor between 1995 and 2004.
Mr Greiner was appointed the inaugural chairman of the O’Farrell government’s advisory body Infrastructure NSW after the March 2011 state election which swept Labor from power. He stepped down from the role in July.
Mrs Greiner was mentioned in a Sydney Morning Herald article in 2011, having told a friend she was glad to be so busy herself, because it kept her out of Nick's way.
Asked about the comment, Mr Greiner said: ''I think when you've been married a very long time it is not all that easy and I think there is some point in her comment that the only way it really works, in the sort of case of people like us, it works if there's a fairly large amount of space because otherwise it becomes more difficult.''
The couple have a son, Justin, and daughter, Kara.
Kathryn is the daughter of Sir Bede Callaghan, the former head of the Commonwealth Bank.
An earlier version of this story incorrectly stated that Mrs Greiner served as a councillor only until 1999.