A post mortem revealed that British tourist Iain Armstrong, 40, died of a brain haemorrhage, according to local media reports.
The British account manager, who worked for a software company in Norfolk, was allegedly beaten to death by Greek supermarket owner Kostas Skarmeas, 54, whose wife he was having an affair with.
Mr Armstrong was found dead at the Hotel Familia in the town of Vathy, Ithaca, on 17 November by the wife of Skarmeas, a SOuth African national.
Mr Skarmeas reportedly told Greek authorities that he had only punched Mr Armstrong twice in the incident. He had demanded, “What are you doing with my wife?” The wife, present during the beating, told the police that she had spoken to Mr Armstrong afterwards but he insisted that he did not need medical treatment.
She found him dead the next day with an empty bottle of cognac found empty beside him, according to the defence lawyer.
The estranged wife of Mr Skarmeas said that Mr Armstrong was a friend who was helping to support her over her long-term marriage problems.
Mr Skarmeas said he was remorseful for the incident which local media reports had occurred because he was worried that his estranged wife was planning to leave Ithaca with his daughter, aged eight.
The case will be heard on the nearby island of Kefalonia.
The family of Mr Armstrong told the BBC that his death has caused them “total devastation”. They said he had travelled to Ithaca “to support a good friend who was in difficulty”.
“This kindness resulted in a physical attack which caused his death,” they said.