Natisha Anderson, 34, was arrested on Feb. 7, 2012, when officers went to 1240 Camelia Drive after Anderson called 911 to say she "cut" her boyfriend, police said.
The boyfriend, 34-year-old Charles Perry, was found suffering from a stab wound to his femoral artery and a steak knife was found in the sink, prosecutors and police said.
Perry was taken to Stanford Hospital, where he succumbed to his injuries, police said.
Anderson told officers that she "accidentally stabbed" Perry, the father of her 4-year-old son, during an argument, prosecutors said.
She was arrested and charged with murder with an enhancement for use of a deadly weapon, according to the San Mateo County District Attorney's Office.