Paul Peccioli, 55, "reacted badly" when Julia Pickup, whom he met online, told him she thought they should stop seeing each other, a court heard.
When Miss Pickup, 51, told him that their six-month relationship was over he banged his head against a wall then held up an airgun, telling Miss Pickup he would "deck her if she was a man", Leicester Crown Court was told.
The court heard that over the next few days Peccioli, a former Conservative member of Daventry District Council, slapped Miss Pickup's legs and threatened to take an overdose.
When she tried to go to work one morning, four days after she had ended their relationship, Peccioli blocked her path.
But he allowed her to call in to explain her absence. Two workmates realised something was wrong and went to her home.
When they arrived at the property in Ullesthorpe, Leicestershire, Miss Pickup escaped but Peccioli chased after them in his own car.
Mr Thatcher told the court: "She ran out to the waiting car. When Peccioli realised what was happening he ran out after her, screaming."
Miss Pickup's colleague did not know the village and turned into a cul-de-sac.
Peccioli tried to open the doors of the car, forcing Miss Pickup's colleague to mount the pavement. They managed to drive away, but Peccioli was following at high speeds.
Miss Pickup's colleague drove to the nearest police station where Peccioli was arrested.
He pleaded guilty to putting a person in fear of violence by harassment and blamed his driving on "emotional upset".
The couple met via the internet in March last year, but Miss Pickup ended the relationship in September after Peccioli became "possessive and overbearing".
Peccioli was given a 12-month suspended prison sentence and a restraining order that prevents him from going within 50 metres of Miss Pickup's home or contacting her.
Judge Michael Pert QC said: "I am prepared to accept that at this late stage of your life you have made a fool of yourself rather than being an inherently dangerous person.
"But that is of little consolation to your victim, and I have to take steps to protect her. Your behaviour during this incident was disgraceful."