Mohammed Almansouri, 39, is accused of murdering Texan Kenny Horack in the Perth suburb of Subiaco in August last year.
The court has been told both of the men were in a relationship with the same man, and the stabbing happened when Almansouri’s pent up jealousy and anger boiled over.
Prosecutors say Mr Horack was repeatedly stabbed.
Almansouri, who is from Qatar, has pleaded not guilty.
His lawyer told the court Almansouri maintained the murder was not the result of a jealous rage, instead claiming that he had acted in self defence.
His lawyers also say there will be evidence at the trial of another man being in the house at the time of stabbing.
The trial is set down for two weeks.