A councillor who stabbed his wife nine times with a kitchen knife after discovering her affair with the postman has been jailed for 20 years. Joseph O'Riordan, 76, was found guilty of attempted murder after his wife Mandy, 47, was left with life-threatening injuries to the chest, torso and back at their home in Polegate, East Sussex. The former Polegate town councillor had become suspicious of his wife's movements and placed a GPS tracker on her car as he hired a private detective to watch her, a court heard. Guilty: Joseph O'Riordan, 74, stabbed his wife Amanda, 47, (pictured together above) nine times with a kitchen knife at the home they shared in Polegate, East Sussex, after discovering her affair with postman Nick Gunn . He soon discovered his estate manager wife was having an affair with married postman, Nick Gunn, nicknamed 'Tommy' by friends and family, who lived and worked in their village. It was revealed yesterday that the 41-year-old postman had had previous affairs with women on his rounds. Brighton Crown Court  heard how O'Riordan repeatedly stabbed his wife in their bedroom of their ground floor flat on October 22 last year, after arguing about the affair. Ambulance crews arrived to find his wife lying on a blood-soaked bed and she was rushed to hospital, where she underwent six hours of emergency surgery to save her life. Nick Gunn: He had affairs with women on his rounds . O'Riordan directed officers to where had left the nine-inch kitchen knife he had used to stab his wife in an 'icily calm manner', the court heard. The former nightclub owner denied attempted murder but a jury took two hours to find him guilty yesterday and he was handed a 20-year prison sentence by Judge Shani Barnes today. He will serve half behind bars and the rest on licence and was also handed a restraining order, banning him for ever contacting his wife directly or indirectly. Sentencing, Judge Barnes, told him: 'You had dedicated your life to serving your community and conducting works for charity. 'But like most of us we are not all good and bad. 'The damage you have done to her is absolutely terrible. 'You have not taken responsibility of what you did to her that night,' the Hastings Observer reports. After the hearing, Detective Chief Inspector Mike Ashcroft, of the Surrey and Sussex Major Crime Team, said: 'We are pleased to have secured a conviction and salutary sentence in what has been a tragic case. 'It could so easily have been a murder investigation and I would like to pay tribute to the victim, Mrs O'Riordan, for the fortitude she has shown throughout.''In sentencing her husband for the attack in which he stabbed her several times, Judge Barnes said O'Riordan had shown no true remorse for what he had done, and he was a man who had enjoyed the control over Mrs O'Riordan. 'As he felt that control had gone, he took a calculated decision to attempt to kill his wife.' The couple had been married for ten years and had attended the Queen's garden party in 2013 for O'Riordan's work on the Diamond Jubilee celebrations. Mrs O'Riordan was a 23-year-old divorcee when she met the older O'Riordan in 1991. They married in 2004 and were seen by many friends as the 'perfect, loving couple'. But as O'Riordan became older his wife essentially became his 'carer' and the court heard how she wanted more 'freedom'. Prosecutor Dale Sullivan said O'Riordan had 'clearly lied' when he told police officers repeatedly that he had stabbed his wife because he had 'just found out she was having an affair'. In reality he had known for weeks that she was seeing Mr Gunn. When Mrs O'Riordan gave evidence last week she did so from behind a screen so she did not have to see O'Riordan. She told the court: 'I loved Joe. I didn't want to hurt him. I never wanted to hurt him – even now.' O'Riordan (left) was convicted of attempted murder after a jury took just two hours and ten minutes to unanimously find him guilty of trying to kill his wife with a nine-inch kitchen knife (right) in October last year . O'Riordan was sitting on Polegate Town Council when he grew suspicious that his wife, Amanda, 47, was having an affair and hired a private investigator to follow her which confirmed her relationship with Mr Gunn . Last year – despite having married three years ago and having moved with his wife Sara Saunders to Portslade, near Brighton – Mr Gunn and Mrs O'Riordan became lovers. But she was not his first, it is claimed. A 39-year-old former partner, who did not want to be named, said: 'We split up because he was having an affair. I saw that he had made a comment on Facebook about a "lover" and I knew he wasn't talking about me so I confronted him. 'He admitted he had been sleeping with a woman he had been delivering post to. He told me that something similar had happened with a previous girlfriend as well. We were together for six years, and this might have happened more than once. I didn't find out until July 2011.' After that affair Mr Gunn married schoolteacher Miss Saunders, who said last night: 'I'm still married to him at the moment and I'm not interested in talking about him.' Mr Gunn has a Facebook page and describes himself on Twitter as: 'A Gamer, a Lover, a Postman and a friend of Death.' As the affair developed last year, O'Riordan first hired a detective to watch his wife and then set up a GPS tracker on her car. The £300 tracker reported back via text to O'Riordan's phone whenever his wife left home and gave the exact location of her vehicle. On one day alone on October 9 the tracker sent a total of 35 notifications to O'Riordan as his wife visited Mr Gunn at his then home in Portslade. O'Riordan used to run nightclubs in the South East before he retired and was also a councillor in East Sussex and became president of his local Royal British Legion. Friends and family of Mrs O'Riordan arrived at Brighton Magistrates' Court (left) for the verdict today while O'Riordan's son Liam - from a previous marriage - also attended the hearing to see his father convicted . O'Riordan was sentenced to 20 years in prison for attempted murder at Brighton Crown Court (pictured above)
Councillor Joseph O'Riordan found guilty of attempting to murder his wife.
Court heard attack occurred after he discovered her affair with the postman.
Amanda O'Riordan, 47, in extra-marital relationship with married Nick Gunn.
Postman Mr Gunn, 41, had previous affairs with women on his rounds.