"One of us has to go, it's either you or me," Keith Raymond Omundsen told his wife as he held a shotgun pointed at her chest.
The couple, who have been married eight years, had been having troubles in their relationship for the past three years due to smoking and alcohol, police prosecutor Sergeant David Grey said.
They were at home on September 30 when Omundsen, 69, said he had something to show the victim, and went upstairs, Mr Grey told the Whanganui District Court yesterday.
The former school teacher came back down the stairs with a shotgun, with two cartridges inserted in the barrels, Mr Grey said. As he walked down the steps, he snapped the shotgun shut and pointed it at the victim's chest as he stood "only a metre away".
The victim "tried to remain calm". After he said one of them had to go, the victim turned her back and went down the stairs.
When spoken to by police, Grey said he was "annoyed" with his wife for smoking and "wanted to intimidate her".
Omundsen pleaded guilty to unlawfully carrying a firearm and threatening to kill.
Defence lawyer Roger Crowley said his client had no previous convictions.
"As a result of this incident he has lost his marriage of eight years," Mr Crowley said.
He said Omundsen was remorseful.
Judge Cameron fined him $800, $130 court costs, and ordered him to pay $1500 emotional harm reparation to the victim. He also ordered the destruction of the gun.