A gay man plead guilty April 1 to voluntary manslaughter in the stabbing death of a man he was dating in National City in 2007 and also to attempted murder of a man who tried to stop the attack.

An 18-year “stipulated sentence” in state prison will be imposed on Fernando Enrique Valenzuela, 47, of San Diego, for the death of Arturo Ponce, 28, said Deputy District Attorney Claudine Ruiz. Valenzuela and his attorney agreed to accept the 18-year term.

Valenzuela also plead guilty to felony assault of Fabricio Zazueta, who tried to stop the attack, and to burglary on Ponce’s residence in National City, where the incident took place on Alpha Street, around 5:15 a.m. on July 1, 2007.

Chula Vista Superior Court Judge Esteban Hernandez set sentencing for June 11 and dismissed a murder charge. Valenzuela remains in the Downtown San Diego central jail on the medical floor without bail.

“It was a good outcome to both sides,” Ruiz said.

Ruiz said members of Ponce’s family will attend the sentencing, and they want to make a statement about his life and how his death has affected them. Valenzuela stabbed Ponce 28 times, inflicting at least 20 wounds to his back, said the prosecutor.

Valenzuela’s attorney, Julie Gibson, said she helped structure the guilty plea so the sentence would be “a set number of years” rather than an indefinite term, such as a 15-years-to-life sentence if he was convicted of second-degree murder. “My client didn’t want a life sentence,” she said.

Even with an 18-year term, Valenzuela would have to serve 85 percent of it, said Gibson. Valenzuela attempted suicide after the slaying, slit his wrists and took all of his psychiatric medication for bipolar disorder, she added.

San Diego Police assisted National City Police in finding Valenzuela who was discovered lying on the floor of his home on South 46th Street. They found empty prescription bottles on the floor and rushed Valenzuela to a hospital.

Gibson said Valenzuela and Ponce had just come back from Tijuana, where they had been visiting Valenzuela’s mother. Gibson said Valenzuela has no prior record and no history of violence. She said he grew up in a large family, with 11 other siblings.

The other victim, Zazueta, told a judge in the April 2008 preliminary hearing that he had taken a knife away from Valenzuela in the struggle.

He said Valenzuela bit him on his left wrist, and he suffered cuts during the struggle. He received treatment at a hospital. A neighbor testified she called 911 after hearing screams outside.