Martin Cook subjected the woman to years of psychological torment by turning up outside her home, workplace and the primary school where she took her children.
She took to sleeping downstairs at her home in Beeston, Leeds, through fear that Cook might break into the property and killer her and her children.
Leeds Crown Court was told the victim also had to resign from her job as a teacher as Cook kept turning up outside the school where she worked and talking to parents about her.
Cook was sentenced to 25 months in prison after pleading guilty to two offences of stalking.
The offences were committed between February and May this year but Cook has previous convictions for harassment and breaching court orders in relation to the same woman.
Ken Green, prosecuting, said Cook was arrested in February this year after the woman reported him for hanging around outside her workplace and outside her home.
Cook denied any wrongdoing and was released on bail while an investigation took place.
The offending continued when Cook turned up outside St Luke's Primary School, Beeston, on May 16 this year as she collected her children from school.
Cook cycled past her on a bike the following day as she walked along Hunslet Hall Road at 8.30am.
The defendant was seen outside the school on a further a occasion as the victim was dropping her children off.
The mum also spotted Cook in the car park outside outside her home and he appeared to be laughing at her.
Mr Green read a victim statement to the court on behalf of the woman.
She said the psychological trauma she had suffered was "insurmountable."
The prosecutor said: "She fears leaving her home and her children.
"She is unable to sleep.
"She doesn't sleep upstairs because she fears that the defendant will break in to the house and possibly murder her and her children."
"Since 2017 she refers to being subjected to a campaign of stalking."
The court heard the woman had been forced to change her job and had taken time off sick due to stress.
Simon Perkins, mitigating, said Cook, of no fixed address, was sorry for what he had done and accepted he would be facing a prison sentence.
Mr Perkins said Cook was now in a relationship with a new partner and wanted to put the offending behind him.
Judge Geoffrey Marson, QC, said: "You were hanging around her home, on her route to work and in the vicinity of where she was dropping off and collecting her children.
"You will appreciate that silence can very often be as intimidating and threatening as words.
"What you were doing was wholly unacceptable. It better not happen again.
"I am not persuaded that there is any real remorse for what you did."