An eyewitness said the woman was running down the street, trailing blood. Her husband was reportedly following in an SUV.
A witness said the suspect got out of the vehicle and yelled at the victim before "punching her with a knife, all over her body."
The woman passed out on a driveway, where she was later pronounced dead.
The suspect was taken into custody without incident.
The incident occurred on Sedona Drive in the Higgins Ranch neighborhood of Chino Hills.
The man and woman are reportedly married and have three children together. A neighbor said the man had moved out of the couple's house about a year ago.
The names of the suspect and victim were not released.