The woman, who got married in 2011, to Premkumar of Mettupatti, alleged that her husband had an illicit affair with another woman, and was torturing her to permit him to marry that woman also.
He also forced her to sign the divorce papers, she alleged.
Though she had given a complaint to the Vadipatti Police station, they did not take any action, she claimed.
The woman, who had come to the collector's office with a bottle of kerosene, doused herself and her baby with the fuel, police said.