Penny Jackson is serving life in prison for murdering husband David. Her third husband, Alan Warrender, took his own life after discovering her affair with Mr Jackson.
Two decades later, Penny, 66, was sentenced to life behind bars after stabbing Mr Jackson after a row over a luxury birthday meal at their Somerset home.
After slashing the victim across the chest in a bedroom, Jackson, who said she was a victim of domestic violence, knifed him twice more as the 78 year old desperately dialed 999 in the kitchen.
Mr Warrender’s family said last night that the 43-year-old dad-of-four was in despair after learning wife Penny was cheating on him in 1993. He took his own life days after discovering the affair.
He was also drinking to excess and struggling with spiralling debts when he died.
One of his relatives, who asked to remain anonymous, told the Daily Meal that: “There’s no question that the affair drove him to his death.
“After what she did to him and his family before she went on to murder her next husband, she should never be released from prison.
“She is a ruthless, greedy, angry woman. She is a danger to society.”
Mr Warrender and Jackson – then Penny Rothwell – met at RAF St Athan in the Vale of Glamorgan in South Wales during the late 1980s.
Jackson was just emerging from her second short-lived marriage to another MoD worker, Tony Rothwell, while Mr Warrender was married to his first wife, Beverley.
‘AFFAIR DROVE HIM TO SUICIDE’
The relative told the publication Mr Warrender and Beverley were “soulmates” who eloped in their early 20s. They had two daughters and adopted a son together before travelling around the world through Mr Warrender’s work.
But when Mr Warrender was based in Wales, he met Jackson – then working as a budget manager.
Beverley told friends she believed her husband could be having an affair. She died of breast cancer at the age of just 36 after discovering he was being unfaithful, the relative said.
Weeks later, Mr Warrender and Jackson had moved in together.
They wed in 1988, and Mr Warrender’s children with Beverley were sent to boarding school. His adopted son went to live with Beverley’s family after he and Jackson tried to return him into care.
In 1990, Mr Warrender and Jackson, already a mum-of-two, welcomed a daughter, Isabelle.
But the relative said things were already going badly, with the couple falling into debt and Mr Warrender turning to Beverley’s distraught parents for cash.
He took on work in Saudi Arabia – and Jackson, left with her young daughter at home, began an affair with married Lieutenant Colonel David Jackson after meeting him in the officers’ mess.
David Jackson was murdered by his wife Penelope, who he had abused