The man was identified by police as Per Torben Lindgren, 58, after his relatives in Sweden had been informed of his death.
Officers from Chalong Police Station quoted Lindgren’s wife as saying she left home at about 1 pm to go shopping.
The wife, who was not identified by name, returned about 3.45 pm to find the house locked from the inside, police said. After gaining entry, according to police, she found Lindgren’s body on a bed. It appeared he had slashed his throat and bled to death, police said.
Investigations were ongoing. The man and the woman had been together for about three years in Phuket, the officers told Phuketwan.
The woman reportedly told investigators her husband was suffering from a lung disease and had expressed the desire to end his life.