Daniel Childs, 36, barricaded the woman in her own bedroom for 45 minutes and told her: “The only way you’re leaving here is if you’re dead.”
He also punched her in the head and back, leaving her with bruises and impaired vision, Shrewsbury Crown Court heard.
The drunken assault took place in the woman’s Telford home on December 31 last year, when the defendant was described as drunk to the point of being “paralytic”.
Prosecutor Mr Rob Edwards told the court yesterday that Childs had been in a relationship with the woman for over a year and that she had children of her own who she cared for.
The woman told police the relationship had been “toxic and vile pretty much from the start”, and the two did not live together permanently but would stay together for periods.
Judge Peter Barrie said that he accepted Childs was not trying to kill the woman with the pillow but added: “What you did do was try to suffocate her with a pillow to the point where she blacked out.
“She was a vulnerable person in her own home.”
He said that far from being an excuse, the fact that Childs was drunk at the time and incapable of controlling himself was an aggravating factor.
The judge handed down a sentence of 15 months in prison for a single charge of assault causing actual bodily harm.
Childs, of Ironbridge Road in Madeley, was also ordered not to contact the victim in any way for the next 10 years.