A Gainsborough man attacked his ex’s new partner in the street, Lincoln Crown Court was told.
Stephen Grocock turned up outside a house party in Garfield Street, Gainsborough, where his former wife Holly was inside with Kyle Byrne.
Siward James-Moore, prosecuting, said: “Kyle Byrne was there with his partner Holly Grocock.
“Stephen Grocock was her ex-husband. They had been separated for a few weeks or months.
“The defendant was not able to come to terms with that. Matters were very raw.
“He harboured animosity to Kyle Byrne who was the new boyfriend.”
Mr James-Moore said that during the evening Mr Byrne received a phone message from Stephen Grocock which indicated Grocock was nearby. As a result Mr Byrne went outside.
He said: “As soon as Kyle Byrne went outside it was a matter of seconds before the defendant appeared.”
The prosecutor said that Grocock spoke to Mr Byrne and then set about him.
He said: “The two of them ended up grappling together on the ground.
“People spilled out of the house. They saw the defendant on top of Kyle Byrne. The defendant was extremely angry.”
The party host eventually got between the two men. Grocock walked away and then drove off.
He was arrested in the early hours of the morning after being stopped on the A1.
Mr James-Moore said that Kyle Byrne was battered and bruised.
He said: “He had bruising to his scalp, swelling to his eyes and his hands were swollen.
“The defendant was uninjured but he had some cuts to his hands.”
When Grocock was interviewed he said he went to the party to speak to his wife.
He claimed Byrne attacked him and that he defended himself.
In court Grocock, 43 , of Middlefield Lane, Gainsborough, initially denied assault occasioning actual bodily harm between March 14 and 17, 2014 but changed his plea to guilty during his trial.
He was given a 12 month community order with 150 hours of unpaid work and was ordered to pay £600 compensation and £600 prosecution costs.