The incident took place here yesterday night, they said.
The deceased was identified as 52-year-old Waseem.
"Babli came to know almost four days back that her husband Waseem had secretly solemnised a court marriage with a 35-year-old woman of the locality around ten days ago. This had led to heated arguments between Babli and Waseem. Later, she killed her husband. The woman has been arrested," Senior Superintendent of Police Rohit Singh Sajwan said.
The police official said that after Waseem's death, the woman informed her brothers-in-law and even started preparation for the last rites. However, someone informed the police.
Babli had married Waseem almost 27 years ago and they had three children.
Yesterday, Waseem had allegedly tried to pressurise Babli to accommodate his second wife, which she declined. Following the quarrel, Waseem went off to sleep, the official said.