Narendra Kumar Singh, who also own a petrol pump, had gone to the accused's house in Obri village under City Kotwali police station area here last night when she and her family chased him and stabbed him with sharp-edged weapons.
Singh's family rushed him to the district hospital from where he was taken to a hospital in Lucknow. He was declared brought dead there, police said.
Police later arrested the woman, her parents and sister and recovered the weapon used in the crime.