Danny Hutchison (43), a former Army clerk, now a store detective, rowed with Navada Mungall over whether they could afford a night out.
He then lost his temper and burned a box of her underwear before hitting her head off a wall.
Despite the attack, Ms Mungall (45), whom he had been seeing for a year, wants him back, Falkirk Sheriff Court was told.
Prosecutor Samantha Brown said an argument flared in Hutchison’s flat in Bo’ness.
She said: “About 9pm they were in the kitchen and she asked him if they were going out for the evening. He advised her that they couldn’t afford to go out and an argument developed in relation to that.”
Hutchison, who admitted he had ‘Services issues’, “got angry” and Ms Mungall asked him to take her home.
Miss Brown said: “The argument continued and the accused got hold of a box containing some of her possessions – I think it was underwear. He took it out of the house to the car park outside and set it on fire.”
The court heard that this caused Ms Mungall to grab more of her belongings in a bid to take them out of the house to safety and put them down outside the door to the common close of the flat.
Hutchison pushed her out of the common close door and grabbed her by the jacket with one hand and by the jaw with the other.
Miss Brown said: “He pushed her backwards causing her to bang her head on the roughcast wall.”
He then pushed her down on top of the bags of clothing she had put outside, called her a “f*****g cow” and walked towards his car.
The court heard he threatened Ms Mungall that if she was still there by the time he returned he would “kill” her. He then drove to Bo’ness police station to report the argument and that Ms Mungall had scratched his face.
Miss Brown said: “For what it’s worth, in her statement she accepts that she scratched his face as part of the ongoing altercation during which she says he was trying to get on top of her.”
Sheriff Derek Livingston said: “Presumably in self-defence.”
Miss Brown replied: “That’s the explanation.”
Ms Mungall then contacted her sister who took her to hospital where medics found the had cuts and abrasions to the back of her head and petechial haemorrhaging round the eyes.
Hutchsion pleaded guilty to assaulting Ms Mungall to her injury by pushing and pulling her and causing her to strike her head.
An allegation that he had also kicked her and seized her by the neck with his hands and applied pressure, so that she had trouble breathing, was dropped by the Crown.
Defence agent Simon Hutchison said it would be “an appropriate approach” to get a background report.
He said: “There are issues Mr Hutchison told me about arising from his time in the Services.”
Sheriff Livingston deferred sentence until July 14, but agreed to lift a bail condition keeping Huthison and Ms Mungall apart after she wrote two letters to the court pleading to be allowed to rebuild their relationship.
He said: “The complainer’s letters indicate that accused has had certain issues and that supervision would assist him.”
Outside court Ms Mungall said: “We just want to be left alone to get on with out lives.”
Before the incident happened, Hutchison had been due to compete in this year’s Invictus Games for wounded service personnel, and had his picture taken with Prince Harry, president of the games, at the UK team trials.
He previously told how he was serving in Kabul in 2008 when his vehicle was blown up by a 12-year-old suicide bomber pushing a wheelbarrow.
However, he was exposed as a “bloater” – a person who embellishes their service history – by real veterans through their Walter Mitty Hunters Club Facebook page.
He later came clean, saying in an open letter: “I want to stand here, cap in hand, and officially apologise whole-heartedly for the lies I have told.”
Four soldiers died in incidents similar to those in Hutchison’s claims, but he doesn’t appear on any official record as a casualty of the conflict.
Last year, after coming through a qualifying event in Las Vegas, Hutchison earned a call-up to the Warrior Games in Virginia and won a bronze medal for wheelchair basketball.