Jason Spragg, 42, suddenly attacked his partner at the end of a shopping trip, Wolverhampton Crown Court was told.
She was in Bloxwich High Street on crutches after a hip replacement operation when he called to find out where she was on October 15 last year, Wolverhampton Crown Court heard.
The defendant was very agitated and wanted to know where they were going to spend the night, said Ms Elizabeth Power, prosecuting who explained that his partner had sold her home and was preparing to buy a caravan for the couple who had been together since the previous January.
They went to a nearby pub which they left at 4.30pm and headed for an alleyway because he wanted to roll a cigarette.
While there he inquired once more about where they were going to stay and was told she was thinking of going to the police to see if they could suggest a hostel or refuge.
This sent him into a rage and he launched a ferocious attack on her during which he repeatedly punched her in the face and stomach, revealed the prosecutor.
Ms Power continued: "She recalled the defendant pulling her to her feet and said she thought he was going to kill her.
"It was a sustained, repeated and unprovoked attack on a vulnerable person on crutches."
Then a passing female motorist saw the fracas and sounded her horn.
Spragg turned to look at the driver, shrugged his shoulders and walked away leaving her to look after the badly injured woman.
She was taken to Walsall Manor Hospital where it was discovered she had suffered brain contusion, a fractured nose, a cheek laceration as well as very bad bruising around both eyes, her neck and jaw.
The defendant was traced soon afterwards and had blood on his hands when arrested.
Mr Oliver Woolhouse, defending, said: "Both had a chaotic and volatile lifestyle. They also had a shared interest in drinking and it was a mutually destructive relationship. He does not want to defend his actions."
Spragg, of Clifton Close, Willenhall, who had previous convictions but not a history of violence, was sent to prison for two years and four months by Judge James Burbidge QC who told him: "I accept that you are remorseful now but you were remorseless in that attack which fortunately was stopped by a passer-by."