A woman drew a 23-year prison sentence Wednesday for killing her alcoholic boyfriend by lacing a jug of margarita cocktails with antifreeze at her apartment in western New York.

"It's not as if you were captive in this house," Judge William Kocher said in imposing a near-maximum penalty on Cynthia Galens, who maintained that victim Thomas Stack was emotionally and physically abusive. "It's just senseless what you did."

Galens, 52, was convicted of manslaughter in September and faced anywhere from five years to 25 years in state prison.

"I accept the consequences of my actions," she said. "I am sorry for all the pain I caused everyone. I'm really sorry."

Galens was charged with murder in January, three months after Stack, a 48-year-old Air Force veteran, died from complications of ethylene glycol poisoning. A grand jury later opted for a first-degree manslaughter charge and Galens turned down an offer to plead guilty in exchange for an 18-year sentence.

State police say Galens insisted she wanted to make Stack sick, not kill him, by mixing the toxic automotive chemical into a store-bought container of margarita mix. She said she placed the cocktail in the refrigerator and went to bed early on Oct. 2, 2009, predicting he would drink it. She said Stack drank most of the 1-gallon jug.

Stark was "feeling poorly" the next morning, she said, but she left at noon to visit the grave of her teenage son, who died of a drug overdose in 2005. When she returned at 4 p.m., she found him unresponsive, foaming from the mouth and breathing loudly.

She said she first called David Galens, her ex-husband, and when he showed up some 20 minutes later, they agreed to call an ambulance. Galens didn't tell paramedics about the antifreeze.

The judge said Galens had "many opportunities to undo what she had done" over a 30-hour period.

Instead, prosecutor R. Michael Tantillo noted, she chose for Stack "a slow and agonizing and horrific death" by telling doctors she had "no idea what he may have ingested."

Galens worked for 30 years at a Veterans Affairs hospital in Canandaigua and met Stack there while he was being treated for alcohol abuse in 2007. They lived on and off at her home in nearly Farmington, a bedroom community 25 miles southeast of Rochester.

Stack was stationed at California's Travis Air Force Base from 1982 to 1986 and later worked as a radiation technician at a nuclear power station. In 2008, he served three months in jail for threatening to kill Galens' former husband and their 16-year-old daughter.

Based on his history of alcoholism, bipolar disorder and depression, state police deemed his death an accident or possibly a suicide. But during a trip to Clearwater, Fla., in early January, authorities say Galens told a friend what she had done — and her friend went to the police.