Gavin Donnelly started a "revenge" fire which left smoke billowing from the victim's semi-detached Berwick home, and even infiltrated her neighbour's.
Newcastle Crown Court heard the victim was thankfully not at her property at the time of the attack, but the neighbour was left in a panic and "in a high state of anxiety over what had and what could have happened".
Prosecutor Michael Bunch said Donnelly, a former soldier who has previous convictions in Scotland, had met the woman through mutual friends at the start of this year.
The relationship gradually deteriorated and in May the 22-year-old turned up at her house, and held a knife to his own throat.
The victim managed to calm the situation by telling Donnelly she loved him but she later started getting abusive texts, including one threat that he would "stab her grandmother".
Mr Bunch told the court: "When she woke the next morning she found messages from the police, telling her her house had been set on fire.
"The defendant also posted further messages, saying 'play with fire by cheating, then you get burned'."
The court heard after he stared the fire, Donnelly fled to the West Coast of Scotland and was tracked down in Ardrossan.
Donnelly, of no fixed abode, admitted arson being reckless to life endangered and sending malicious communication.
He also admitted common assault and criminal damage in relation to an earlier row where he had punched the victim and threw items, including a television, around the room.
The court heard he has previous convictions, including offences of threatening behaviour, stalking and assault, which were dealt with in the Scottish courts.
He was on bail and a community order at the time of the fire.
Susan Hirst, mitigating, said Hirst had a traumatic childhood and suffered from post traumatic stress disorder.
She told the court Donnelly had received help with his mental health problems while in custody on remand, and "wished to apologise for what he has done".
She added: "He is now receiving the help he clearly needs.”
Judge Stephen Earl sentenced Donnelly to four years and six months behind bars.