Not a lot of detail in the article:

http://www.mirror.co.uk/news/weird-worl ... -22909444/

Furious wife cuts off cheating husband's penis in revenge for affairs

by Andrew Gregory, Daily Mirror 9/02/2011

A WIFE cut off her cheating husband’s penis after a string of blazing rows over his affairs and boozing.

Police said Hea Jung, 26, did the deed after waiting for hubby Chol Jung, 52, to pass out drunk at their home in Sunchang, South Korea.

Passed out drunk, probably didn't even know or realize what was happening to him. I think there have been several men who were castrated by their lovers after getting loaded, bombed, passed out drunk. I also remember one man saying he got drunk and castrated himself. He started drinking, after an hour or so he banded his testicles, kept drinking, passed out and when he woke up his scrotum and testicles were dead. He had a terrible hangover, so he waited until he felt good enough to drive to the ER. His balls had been banded for over 18-20 hours before he finally saw a doctor. Not sure what happened specifically after that, but he walked out without his testicles. I guess getting really drunk puts you in a "no-pain" zone. I have never been that drunk.