Balbinder Singh had been overheard by his girlfriend talking to another woman, on loudspeaker on his phone while he was in the bath, who called him "babe" during the conversation in October 2020.
Newcastle Crown Court heard his girlfriend "lost her temper" and threw him out of her home, without giving him the chance to get dressed.
She then said she was going to confront the other woman and set off for Frederick Street in South Shields, to find her.
Singh, who had put on a dressing gown, said he followed his partner and took a screwdriver from her then "lashed out with it" during the confrontation, which caused an injury to her arm.
Singh, 29, of Saint Jude's Terrace, South Shields, admitted assault and having a bladed article.
The court heard his then girlfriend was not willing to provide a statement to the police about what happened.
Prosecutor Liam O'Brien said Singh accepted his actions were unlawful.
The court heard a witness saw Singh "emerging from his vehicle in a threatening manner" while wearing a dressing gown and disposing of a screw driver down a drain after being ushered away by his mother.
Mr O'Brien said it was a "heated confrontation in the street" and that prosecutors accepted Singh's basis of plea about what happened.
He told the court part of the basis read: "The accused maintains he originally travelled to Frederick Street in South Shields on October 17 2020 to try andprevent his then partner from confronting an acquaintance.
"The accused was concerned that if the women met there would have been an argument and the argument may well have resulted in violence."
Nicholas Lane, defending, said: "He was in his dressing gown, having been ejected form his partner's home.
"In frustration and anger he behaved the way he did.
"This was not a weapon he took with him to the scene, it is a weapon he took from his former partner."
Judge Amanda Rippon sentenced Singh to 20 months imprisonment, suspended for two years, with rehabilitation and programme requirements plus 100 hours unpaid work.