Pornbun Sinthusin, 35, came home in Bangkok yesterday and found her 34-year-old husband Ploeng Plaekratoke in bed with another woman, said police Lieutenant Colonel Kornwat Hunpradit.
She later gave him several beers before cutting off his penis with "a sharp object,'' Lt-Col Kornwat said.
The husband was now in intensive care.
"We suspect she took both her weapon and her husband's penis because we cannot find the penis in their apartment. We even checked a toilet but she did not dump it there,'' Lt-Col Kornwat said.