The accused suspected his wife of infidelity and had allegedly tried to kill her in March by pouring mosquito repellent in her mouth, but she survived, they said.
On December 1, Heera Lal went to the Karawal Nagar Police Station and informed the police personnel that he had killed his 28-year-old wife.
He also told them that he had tried to commit suicide, they said.
The police rushed to the spot and found the woman's body on a bed, with three children aged nine, six-and-a-half and three years also sleeping next to her.
During investigation, six shaving blades used by accused to slit his wrists were recovered and three empty bottles of a mosquito repellent were also recovered, police said.
The accused revealed that he had consumed mosquito repellent and also slit his wrists, police said, adding that he was under treatment but out of danger.
The victim's family members alleged that she was subjected to torture by her husband for many years.
Lal told police that he suspected his wife of having illicit relations and had tried to kill her in March, for which he was sent to jail.
After he came out of jail, he wanted to get rid of his wife and did so on December 1, the police said. The couple got married 10 years back.