GRIMSBY man David Thomas punched his partner three times in a drunken rage after she locked him in their house, a court heard.
Thomas, 26, of Wellington Street, admitted assault causing actual bodily harm to Toni Lolley at their home, on July 26.
The following day he asked his partner how her face ended up so bruised.
Recorder Mark McKone said it was "a disgraceful and cowardly" act.
He added: "You should be ashamed of yourself. She was trying to stop you causing trouble."
The court heard the couple were still in a relationship.
Recorder McKone said: "It is not for me to say whether that is a good thing or bad thing."
He added: "It is time at the age of 26 years that you look after your partner."
The court heard the couple are expecting their first child.
Thomas was given 13 months in prison, suspended for two years.
He was also ordered to do 150 hours of unpaid work and undergo supervision for 12 months with support to address his alcohol problem.
Prosecuting, James Gelsthorpe said the couple had been to the Cleethorpes Air Show in the morning.
They spent the rest of the afternoon and early evening drinking in The Barcelona bar until around 9pm.
There was a confrontation between the couple after a man approached Ms Lolley.
Thomas later tried to shake the hand of the man who had approached his partner in an attempt to reconcile.
He was then attacked by a number of men.
After the confrontation they both left in order to feed their dog.
Ms Lolley said her partner was in a bad mood.
When they arrived home, Thomas grabbed a hammer, shoved it down the back of his trousers and said he was going back to the bar.
Ms Lolley locked all the doors and would not let him leave.
Thomas tried to get out through a window, which resulted in a tussle.
Ms Lolley hid the hammer. In response Thomas scuffled with his partner and punched her three times in the face.
Mr Gelsthorpe said the row was heard by a neighbour who said it went on for half an hour.
Ms Lolley contacted Humberside Police and went round to a friends home.
When she returned to her own home she fell asleep.
She was awoken by Thomas when he returned the next day.
He said: "Who has done that to your face?"
The police attended and Thomas was interviewed.
In interview he said his partner had ben "giving him grief".
The court heard Ms Lolley suffered bruising to her right eye and a cut top lip. She was treated in hospital later.
For Thomas, Richard Hackfath said his client will benefit from supervision and treatment for his alcohol problem.
