According to police, the forty-year-old accused, identified as Rajesh Dandwate, killed his wife Kalpana as he suspected her character.
The couple resided in Vaishali Nagar in Mulund (West), a police officer said adding, "The incident took place this morning. The accused smashed her head with a stone when she was asleep. He killed her as he suspected her of having an extra-marital affair."
After the incident came to light, local residents alerted the police, who arrested the accused.
Dandwate has been booked under section 302 (murder) of IPC, police said.