Violent control freak Matthew Edmonds left his partner so stressed her hair started falling out.
When Edmonds and the woman first starting their relationship, it went well - but his coercive behaviour soon started taking its toll.
A court heard he knocked her front tooth out with a punch, repeatedly falsely accused her of cheating and alienated her from those who cared about her.
He also got her to surrender her phone to him, which he used to send cruel messages to her mum, as if from her, driving a wedge between them.
His grip on her was finally released when a neighbour reported a disturbance and officers who attended found her in a distressed state.
She had started wearing a large hair band to hide the bald patches sparked by the stress Edmonds had subjected her to, Newcastle Crown Court heard.
Now the 30-year-old, who admitted controlling and coercive behaviour and assault, has been jailed for 26 months.
The court heard the couple, who lived together in South Shields, started seeing each other in 2017 and their relationship ended in March last year.
Prosecutor Deborah Smithies said the couple's relationship was initially "good" but Edmonds became angry and threatening while accusing her of "sleeping around" even though she had never been unfaithful.
The court heard the victim had left their home and packed her bags after one argument but Edmonds caught up with her at South Eldon Street in the town.
Miss Smithies said: "He physically attacked her, punching her in the face.
“She said she felt her right front tooth rip out of her gum and fall to the ground, her lips and gums bleeding.
"The defendant picked up her tooth and took her back to the flat.
"He cleaned her up and told her he was sorry."
The court heard the victim was left in pain and told nobody about her ordeal.
Miss Smithies said Edmonds' behaviour started to isolate the victim, whose friends gradually began to stay away.
The court heard the victim handed over her mobile phone to Edmonds' in a bid to stop the accusations he was making about her.
But Miss Smithies said: "He used the handset to send text messages to her mother, purporting to be from her, telling her she was a bad mother.
"He continued to be verbally abusive and controlling in behaviour throughout their relationship.
"The stress of living with the defendant, who was behaving in this way towards her, eventually caused her to start to lose her hair.
"She began to try and compensate by using a large, woollen hairband."
Edmonds, of no fixed address, admitted assault and controlling and coercive behaviour.
As well as jailing Edmonds, of no fixed address, for 26 months, Judge Sarah Mallett imposed a restraining order to keep him away from the victim for a year.
The judge said the physical effect on the victim was a demonstration of the psychological impact and added: "Her hair began to fall out to the extent the hair loss was significant."
Robin Turton, defending, said Edmonds plans to move back to Southampton when he is released from prison and that his behaviour was a product of his "personality and illnesses" he has suffered.
He said he believes he has ADHD and suffers from an emotionally unstable personality disorder.