The victim, Jugnu, was found dead at his house five days ago and his wife Babli had claimed that he had committed suicide by hanging.
However, police said they have arrested Babli after the couple's six-year-old son told them during investigation that his mother had killed Jugnu with the help of Anil, with whom she was allegedly having illicit relations.
A case has been registered against Babli, Anil and one more person for the murder, police said.