A District man accused of starting a house fire that killed his 80-year-old wife told detectives that she had been having an affair with one of their neighbors, according to documents filed in D.C. Superior Court.

At his first court appearance Wednesday, Robert L. Proctor, 76, was ordered to remain in jail until his next hearing Friday.

Authorities allege that on Feb. 13, Proctor set fire to his brick rowhouse in the 4600 block of Fourth Street NW. Lucille Proctor, who was found in a bedroom, died of thermal burns and smoke inhalation, authorities said.

Robert Proctor was arrested Tuesday and charged with arson. It was unclear whether he would face additional ­charges. The medical examiner has not yet issued a homicide ruling in Lucille Proctor’s death.

According to court documents, Robert Proctor returned home shortly after the fire had been extinguished, and detectives seized his clothes as evidence during questioning. In an examination of the clothes, authorities said, they found signs of ignitable liquids that they said had been used to set the fire.

In several interviews with detectives, according to the documents, Proctor said he and his wife argued constantly. The night before the fire, he said, his wife told him that she was going to “get rid of” him by putting him in a hospital.

He told detectives that the next morning, he made coffee and took it to his wife, who he said mostly stayed in her room and needed a walker to get around. He asked her to press his shirts, and she refused, he said.

Between 5 and 5:30 a.m., Proctor told police, he left the house through a rear door, according to court papers, and his wife was in her bed.

Proctor told detectives that his wife was having an affair and that he had confronted her about it on several occasions, the court papers say. He said he wanted a divorce and suggested that they sell the house, but he said she refused. The couple had lived in the house for more than 40 years.

Nearly a week after the fire, Proctor again spoke with detectives and denied setting the fire, court papers say. In one of the police interviews, according to court documents, Proctor said he was “relieved” when he was told his wife died in the fire.

During the hearing, Proctor’s public defender, Madalyn Harvey, argued that there was no evidence her client was “relieved” and that was just an opinion by the detective. She acknowledged that her client’s statements seemed “bizarre” but said that they in no way indicated he was responsible for the fire.

Harvey argued that her client should be released from jail because of his age, frail health and lack of prior convictions. Several family members attended the hearing, and some wiped away tears. They declined to comment afterward.

Family members, according to the documents, say Robert Proctor been previously diagnosed with a mental illness. During the hearing, prosecutors requested a mental evaluation, but Harvey said there was no need, and Magistrate Judge Karen Howze denied the request.