The German, aged 40, bought his Thai lover a car and a bar in Patong after they met seven months ago.
However, she recently left him for another man and sold the bar and the car, acquaintances of the German have told police.
The bar and the German's apartment are both off Nanai Road in Patong, on Phuket's west coast.
An Italian man who has an interest in the apartment block investigated a strong odor about 8pm yesterday and discovered the German.
The man's body was dangling from electrical wiring rigged around a television cabinet.
One whisky bottle and several Leo beer bottles were on a table nearby, along with an ashtray and a pack of cigarettes.
Kusoldharm Foundation paramedics and police estimated the man had been dead for about three days. His body was taken to Patong Hospital.
Police say there were no suspicious circumstances.
German envoys have been told about the death and are contacting the man's relatives. Phuketwan will refrain from publishing the man's name until family have been informed.
It is not known whether the man's former lover is aware of his death.