Former Sen. Pete Domenici (R-N.M.) has revealed he fathered a son out of wedlock more than 30 years ago.

The 80-year-old former lawmaker told the Albuquerque Journal he had promised not to make the news public, saying, “The mother of that child made me pledge that we would never reveal that parenthood, and I have tried to honor that pledge and so has she.”

Domenici says he decided to come forward because he anticipated the story might come out.

The newspaper identified Domenici’s son as Adam Laxalt, a lawyer in Nevada. The man’s mother is Michelle Laxalt, a Washington lobbyist and the daughter of former Sen. Paul Laxalt (R-Nev.)

“I deeply regret this and am very sorry for my behavior,” Domenici said in a statement. “I hope New Mexicans will view that my accomplishments for my beloved state outweigh my personal transgression.”

Domenici, a six-term senator, has eight children with his wife, Nancy. He declined to seek another term in 2008, citing health issues.

Domenici’s paternity announcement comes less than a week after Rep. Steve Cohen (D-Tenn.), who is unmarried, disclosed he learned in 2010 that he fathered a child more than 20 years ago.