joseph o'riordan was sitting on polegate town council in east sussex when he grew suspicious his wife , amanda , 47 , was having an alleged affair and hired a private investigator to follow her .
brighton magistrates ' court heard they agreed to stay together but o'riordan later attacked her - stabbing her in the chest , torso , arms and back .
the couple had been married for ten years when o'riordan , who was also the president of his local royal british legion and had attended the queen 's garden party in 2013 for his work on the diamond jubilee celebrations .