Graham Marchant was given a restraining order to keep him away from his ex girlfriend when he was convicted of harassing her in April last year.
But Newcastle Crown Court, just six weeks after the order was made, Marchant started sending texts.
Prosecutor Neil Pallister told the court the messages were critical about the woman's new relationship, became abusive and led to threats.
Mr Pallister said one text warned that Marchant would "bury her new partner" and another referred to "chopping him the **** up".
The victim said she was left unable to relax and worried Marchant, who appeared to accept he was jealous about the new relationship, would "do something drastic".
The court heard Marchant, who has a criminal record and has been to jail before, used Facebook profiles to send messages to the new man.
Mr Pallister said: "He told him he didn't mind going back to prison and would do some serious damage before he did so."
The court heard Marchant tried to engineer a confrontation in person with the man, who was left "looking over his shoulder" as a result of the unwanted contact.
Marchant, 34, of Melbourne Gardens, South Shields, admitted breach of a restraining order and harassment.
Jane Foley, defending, said: "This was kneejerk reaction to the loss of his long term relationship and having to cope with the acceptance of a new man coming into her life and essentially being an ever-present factor in the lives of his children.
"There has been no problems since these offences occurred last year."
Miss Foley said Marchant has voluntarily sought help since the offences.
Marchant was sentenced to 13 months imprisonment, suspended for 18 months, with programme requirements and a restraining order in relation to the man.
Miss Recorder Amy Mannion told him: "People's relationships break down, thousands of people sadly come to the end of their relationships every year and they don't commit criminal offences because of it, they don't send abusive messages, they behave appropriately.
"You have escaped immediate custody by the skin of your teeth."