The wife of Ewen Macdonald says she feels ''like a fool'' and totally betrayed by her husband.

Anna Guy told the NZ Herald she had lived a double life and felt her marriage had been a sham.

She took her maiden name after Macdonald was charged with the murder of her brother, Feilding farmer Scott Guy.

Macdonald was found not guilty of murder in July, but was sentenced to five years' jail on Friday on theft, intentional damage, arson and graffiti charges.

"Now you think ... now I feel like a fool - it was total betrayal,'' she said.

"I think that's why it was really devastating at the time because I found out so much more about him that I didn't know. It took me most of last year to get my head around it," she told the NZ Herald.

"Getting arrested for killing Scott was one thing but there was way more stuff to come that was so devastating that no one knew about."

Macdonald will be eligible for parole in December, having already served 17 months.

Guy said she was still shocked by her husband's actions, and at times thought she would go insane thinking about what happened.

"But I have managed to switch off a bit now because I figured I would go insane if I thought about it all the time. But I keep going over and over conversations I had with him earlier - what did he actually mean by that?

"He had been through so much with us as a family - then it was like he was a traitor, sort of," she said.

The pair met in high school and married in 2001. They have four children together - Finn, Jack, Lucy and Wade.