The Virginia woman married to Soviet hunger striker Sergei Petrov, who is trying to get permission to emigrate to the United States, said yesterday she would leave Moscow without her husband because she cannot bear to stay and watch him die.

Virginia Johnson Petrov, 24, of Roanoke, Va., said during a news conference in Petrov's Moscow apartment that she had tried to talk her husband out of his hunger strike after she arrived in Moscow Sunday night. "When I came I was not fully convinced, until I saw him, that this is what he wants to do. Now I have seen him and I am convinced this is what he wants."

Asked why she would not accept a Soviet offer to permit her to live in the Soviet Union with her husband, she said: "The whole point of all this is reunification of families. I have a large family in the United States. I find it difficult to believe I could persuade them to come and live here."

"She's leaving tomorrow," Petrov said, sitting on a couch with his arm around his wife. "I don't think I have too much time left. I definitely don't want her to stay here."

Petrov, 29, is a free-lance photographer who began his hunger strike 49 days ago and who reportedly has lost more than 50 pounds so far. Yesterday he ridiculed official Soviet contentions that he could not be allowed to leave the Soviet Union on state security grounds--apparently because of the three months he spent six years ago at a research institute.

"My wife is American. I know a lot of Americans. Suppose I have such kinds of secrets. I could have given them here as well as in the United States. Nobody can make me believe I am such an important figure," Petrov said.

At one point he angrily held up a copy of the Communist Party newspaper Pravda showing the full text of the final act of the Helsinki East-West agreement on reuniting families.

"It is just a piece of paper, nothing at all," he said. "People should fight to make such things real. This is exactly what I am doing."

He said he had been visited recently by a Soviet doctor who had warned him he was in dangerous condition, but he had turned down an offer to be taken to a hospital.

Petrov is one of seven Soviets who began hunger strikes in May and June to gain the right to live with their Western spouses outside the Soviet Union. According to the Associated Press, four ended their fasts after being told they could leave, although only one actually has left the country. One woman ended her protest after being threatened with reprisals and placed under heavy surveillance.

Elena Kusmenko Balovlenkov, a 29-year-old nurse at City Hospital in Baltimore, is married to the seventh, Yuri Balovlenkov. Yesterday she met with emigration officials in Moscow in an effort to win an exit visa for her husband. She told reporters after the meeting that the officials said her appeal could not be answered immediately, but invited her to meet with them again on Thursday.

"They offered to extend my visa on the spot, and encouraged us to remain in the Soviet Union," Elena Balovlenkov said. "But that is out of the question."

Balovlenkov and Petrov both met their American wives in Moscow. The Petrovs, married in 1981, had not seen each other for 17 months before being reunited Sunday. The Balovlenkovs have been married since 1978, but until Saturday they had not been together since 1979.

Elena Balovlenkov arrived here Saturday with the couple's 25-month-old daughter Yekaterina, hoping to convince Soviet officials to let her husband go to the United States or at least to talk him out of his fast.

She also is seeking a meeting with Soviet Foreign Ministry officials, she said, to press her appeal that they force-feed her husband.

Balovlenkov, a 33-year-old former computer programmer, said he continued to feel weak today, the 16th day of his latest fast. He ended a 43-day hunger strike on June 21, saying emigration authorities had promised him permission to leave.

Soviet officials have denied making the promise, however, and told Western correspondents that, like Petrov, Balovlenkov would not be able to emigrate for security reasons.