A friend of Manny Pacquiao, who is suing the boxer’s trainer/coach for allegedly punching him from behind, wants a judge to keep out any evidence during trial of any alleged infidelity by the plaintiff.

Gregorio Asuncion along with his wife, Allyson, sued Freddie Roach and his Wild Card Gym Boxing Club in Los Angeles Superior Court in November 2008.

The suit’s allegations include assault, battery, intentional and negligent infliction of emotional distress, negligence, premises liability and loss of consortium.

Roach — denying Asuncion’s claim that he hit him in the back of the neck — maintains in his deposition that he put his hands “softly” on the plaintiff’s shoulders, calling it a “friendly gesture.”

A final status conference is set for Jan. 6, when Judge Kenneth Freeman is scheduled to hear several pretrial motions. Among them is a bid by Asuncion’s lawyer, Robert H. McNeill, to keep out any allegations that his client broke any of his marital vows.

“Specifically, [the Asuncions] anticipate that [Roach] will attempt to introduce evidence that ... Asuncion was involved in an extramarital affair and engaged in sexual relations with a prostitute at a motel in Hollywood,” McNeill’s court papers state.

During a deposition last August, Asuncion denied being unfaithful to his wife, according to McNeill’s court papers. In any event, McNeill argues, the allegations are not relevant to Asuncion’s case, which deals with an alleged assault.

But Roach’s lawyers maintain the subject is fair game and that they should be allowed to present related evidence to a jury. They say it is relevant to the Asuncions’ claim that their sexual intimacy has decreased as a result of the alleged injury.

“Based on [Asuncion’s] loss of consortium claim ... the probative value of ... Asuncion’s extramarital affairs and sexual relations with prostitutes is very high and outweighs any prejudice to [the couple],” the Roach court papers state.

Both sides also are at odds over whether some witnesses should be able to testify that they believe Asuncion was faking his injuries.

Meanwhile, Roach’s lawyers want to bar evidence of any prior violent conduct by their client, saying it would be prejudicial to his case.

But McNeill wants the information about Roach’s alleged hotheaded past to be allowed. The lawyer’s court papers state that Roach admitted he paid money to settle a man’s claims that the trainer assaulted him at a Kinko’s store about five years ago.

McNeill also argues that another of his clients, writer Alex Pantinos Vidal, alleges in a separate lawsuit that Roach assaulted and battered him in Las Vegas in July 2008 and threatened to kill him if he wrote another story about the trainer.

The plaintiffs’ complaint alleges Gregorio Asuncion had just picked up Pacquiao and dropped him off at the Wild Card Gym in Hollywood on Oct. 20, 2008, when Roach and a number of his associates “intentionally, willfully, wantonly and maliciously threatened to harm him.”

“Because of [Roach’s] skill as a boxer and his occupation as a boxing trainer, a reasonable person in [Asuncion’s] situation would have been offended by the threat of violence by Roach,” the complaint states.

Roach allegedly asked the 52-year-old Asuncion to get out of the gym because he did not want too many people inside. When Asuncion was about to leave, Roach allegedly hit him at the back of the neck, causing him to fall face first on the floor.

Asuncion was treated at Hollywood Presbyterian Hospital for a neck sprain and a contusion to the head, according to his court papers. He is known as “Sheriff” within Pacquiao’s circles because he has worked for more than 25 years with the Sheriff’s Department.