It happened just before 9 a.m. on Friday at a home on Washoan Road, near Zuni Road.
When deputies arrived, they found a 59-year-old man with severe injuries.
"Through investigation, deputies learned the victim had been stabbed at his home he shared with his wife," said the San Bernardino County Sheriff's Department in a statement.
Investigators said the man and woman got into some sort of fight when the man was stabbed.
Deputies then noticed smoke coming from inside the man's home, but the residence was barricaded. Investigators later determined the woman set the house on fire after the fight.
"A family member inside the home was able to safely exit the residence before shots were heard," the sheriff's department said. "The Sheriff's Specialized Enforcement Division (SED) responded and attempted to make contact with the suspect, to no avail. Within minutes, the residence was fully engulfed in flames and nearby residences were evacuated."
The woman's body was found inside the home after the fire was extinguished. The man was taken to the hospital though his condition is unknown.
The incident remains under investigation.