A West Babylon man who stabbed his wife to death during an argument a year ago pleaded guilty Friday to second-degree murder.

In return for the plea, State Supreme Court Justice Richard Ambro in Riverhead agreed to sentence Kerwyn Jaggernauth, 32, to 18 years to life in prison.

Assistant District Attorney Glenn Kurtzrock said Jaggernauth was a possessive husband who followed his wife, Sonja Williams, 32, around.

The couple apparently argued about that issue at about 4 a.m. on Feb. 20, 2016, and Jaggernauth stabbed Williams multiple times while their 13- and 6-year-old sons slept. Jaggernauth then tried to kill himself by slicing his arms and drinking antifreeze, Kurtzrock said.

“It’s a tragedy for all involved,” said Jaggernauth’s attorney, Robert Macedonio of Central Islip. “Two boys are growing up without a mother or a father.”

After the couple’s landlord noticed blood outside the house, she called Williams’ mother, who then called police. They found Williams’ body under a blanket in the basement and Jaggernauth unconscious in the bathtub, Kurtzrock said.

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Williams’ family and friends said they were not happy with the plea deal, but grateful to avoid a grueling trial.

“I hope to God he never gets parole,” said a cousin, Andrea Huie of Hicksville. “He left a whole family in misery. . . . This is really, really, really hard for us.”

Another cousin, Ashley Huie of Baldwin, said the family saw signs of marital problems only in retrospect.

“I think we were all shocked,” she said. “That’s why it’s so devastating.”

It’s also hard because Williams was an unusually supportive and positive presence in many people’s lives, said a friend, Kensasha Branam-Mask of Copiague.

“She was someone who had so much life in her, so much spirit,” Branam-Mask said. “That’s such a rare quality in people.”