Kyle Chauntry turned up 'unexpectedly' at the Posh Meze Grill and Bar, in Kirkby, on July 11, last year, and an argument ensued, said prosecutor Andrew Conboy.
At 12.45am, he followed her on to Urban Road, grabbed her by the throat and pushed her against the wall, he said.
When his wife's sister tried to drag him off her, 32-year-old Chauntry grabbed her by the throat and shoved her away, the court heard.
His wife walked away, but Chauntry pulled her around by the shoulder and shoved her to the ground.
She called him a p**** and Chauntry punched her three times in the face. As he walked away a passing police car stopped and he was arrested.
When he was interviewed, he said his wife slapped him and he simply pushed her away to protect himself.
Ryan Higginbotham, for Chauntry, cross-examined the victim, and she denied being drunk or acting aggressively.
When Chauntry gave evidence, he said he began drinking in the Nag's Head at around 5pm and described himself as 'merry' at the time of the incident.
He said both women got in his face when they were outside. He told magistrates he and his wife sat down on a bench ‘to sort things out’ and he eventually shoved her and she hit the floor.
He left the scene, but 'felt a bit bad' and returned to check on her and call an ambulance.
Probation officer Mark Burton said the incident was triggered by the ‘acrimonious separation from his wife’ after the relationship broke down in 2019.
Chauntry, formerly of Sutton Road, Huthwaite, and now of Murphy Drive, Bagworth, Coalville, denied two counts of assault, when he appeared at Mansfield Magistrates Court, on February 2.
On Friday, magistrates found him guilty of assaulting his wife, but acquitted him of assaulting her sister. They said they ‘couldn't be sure he assaulted his wife in the way that was alleged,’ but found her a credible witness.
He received a 12-month community order with 20 rehabilitation days and 80 hours of unpaid work. He was ordered to pay £200 compensation and a £95 surcharge.