"I need help," Aljarrau Simmons-Waterhouse told police after attempting to harm himself and slapping his partner following a dispute.
Simmons-Waterhouse was at his Whanganui address on August 22 when his partner went to a nearby dairy at 8am to buy him a pie and something to drink.
When she arrived back, Simmons-Waterhouse was not happy with the drink she had chosen, so she returned to the dairy and purchased another.
In Whanganui District Court on Tuesday, police prosecutor Stephen Butler said Simmons-Waterhouse was also unhappy with the second drink and became agitated.
"The victim attempted to stop the defendant from harming himself," Butler said.
"He slapped the victim multiple times in the face. The victim attempted to leave the property while the defendant started throwing things inside."
When police arrested Simmons-Waterhouse, charging him with assault on a person in a family relationship, he told them that he needed help.
Simmons-Waterhouse had been with his partner for approximately four years and in that time there had been several previous family harm incidents between them.
"Mr Waterhouse, the position you find yourself in today, as you know, is one which is always taken seriously by the court," Judge Philip Crayton said.
"Family violence is never acceptable.
"I bear in mind that the complainant wants contact and wants the restoration of your relationship. I can understand that. There is clearly going to be an ongoing relationship."
Judge Crayton sentenced Simmons-Waterhouse to 12 months' intensive supervision.