The former wife of jailed farmer Ewen Macdonald says giving evidence at his murder trial was "probably the worst thing I have ever had to do in my life".

In an interview with 60 Minutes, Anna Guy has talked about the "heartbreaking" impact on her family after her husband was charged with the murder of her brother, Scott Guy.

Macdonald was acquitted after a trial in the High Court in July.

He was sentenced earlier this month to five years in prison for six unrelated charges, including burning down a home on Mr Guy's property and vandalising another property Scott and his wife Kylee were having built.


Ms Guy, who returned to her maiden name after her husband's trial, has previously spoken about how she felt she had lived a double life and her whole marriage was a sham.

Ms Guy told the Herald earlier this month the trust she and her husband developed since they met when she was 15 had been betrayed by Macdonald's lies.

In the 60 Minutes interview, which is being advertised to air tomorrow night as an exclusive television interview, Ms Guy will talk about "what the reality was behind the idyllic relationship portrayed by Macdonald's lawyers during the trial", a MediaWorks spokeswoman said.

She also says her children are the centre of her life.

"At the end of the day, they are my first priority," Ms Guy says.

"I just want to move forward ... and look to the future now."