Owen Grant could not accept seeing his ex-partner Michelle Bradley with another man after they broke up having dated for eight years.
Ms Bradley, from Dunmore, Carrigans, Co Donegal, had changed the lock on her house which she had been sharing with Grant.
However, on September 11, 2009, Grant turned up and demanded the keys for her BMW car, which he had claimed was his.
He grabbed the keys from her and then pushed her to the ground and kicked her in the side.
Later that evening Grant, 44, arrived at her home and broke into it. He set fire to four chairs and burned down the luxury home.
Letterkenny Circuit Court heard Grant, of 447 Imlick Villas, Carrigans, Co Donegal, sought treatment from the Mental Health Services after the attack and spent seven weeks in their care.
However, Ms Bradley, 40, said she still lived in fear of Grant and was terrified he would come after her.
“I am still terrified of him. He threatened to kill me and that’s why I’m still afraid of him,” she said.
Judge John O’Hagan said Grant was not a teenager and he did not accept that he had any great mental health issues.
“He lost it and couldn’t cope with the break-up. He was besotted with Ms Bradley — utterly consumed by her and could not get it out of his mind that this had happened.
“He demanded their relationship be restored and it took over his life. But it made her life a total misery by contacting her again and again.
He added: “There’s no mental health issue here. He’s depressed; so, lots of people are depressed. There is no excuse for what he did.”
He added that it was only by luck that Ms Bradley had not been staying in the house at the time of the arson attack.
He took the common assault into account, but sentenced Grant to two-and-half years in prison for the arson attack on Ms Bradley’s home.
He also ordered that Grant have no contact ever again with his former girlfriend.