Shaun Bennett harangued his partner when he found her but later lost his temper.
Phil Howes, prosecuting, said that Bennett then began to hit the woman.
He said: “He punched her to the face at least 10 times before she lost consciousness.”
During the incident the woman suffered a fractured left cheekbone and a cut to her lower lip.
Bennett, 37, of Harpswell Close, Gainsborough, admitted inflicting grievous bodily harm as a result of the incident on March 24, 2015. He was given a two year community order and ordered to complete a building better relationships course. He was also given a rehabilitation activity requirement of up to 40 days.
The court was told that Bennett had already served the equivalent of a 12 month jail sentence while on remand awaiting his court appearance.
Sunil Khanna, defending, said the victim has since expressed a desire to resume her relationship with Bennett.
Judge Simon Hirst, passing sentence, told Bennett: “People who beat women causing these sort of injuries go to prison. However, in your case you have already served the equivalent of a 12 month sentence. It seems to me that because, and only because, you have served a 12 month sentence I can take an option that may not only help you but may help your victim.
“If you breach the order and are before the court again then custody is inevitable.”