Greta Palacios, a native of Ecuador and a U.S. citizen, met her husband, Alexander, 21 years ago, and has lived with him in Los Angeles ever since.

Last night she was planning to drive him to Los Angeles International airport, where he was to fly out of the country on order of the U.S. government and leave behind his wife and 18-year-old son. Palacios, Nicaragua's consul general in Los Angeles, was one of about 60 Nicaraguan diplomats and dependents ordered to leave the country by midnight Friday.

"I hate to see all of the families that are going to be apart," Greta Palacios said a few hours after the Nicaraguan Embassy here telephoned with the news. "It breaks my heart."

The Reagan administration's decision to expel all Nicaraguan representatives other than those in the embassy is likely to split several families, according to embassy spokesman Angela Saballos.

The action, in retaliation for expulsion of three U.S. diplomats by Nicaragua's Sandinista government Monday, affects consuls and vice consuls not usually caught up in such high-level policy disputes.

Rather than being members of their nation's foreign service who travel from country to country, many of the consuls have been in the United States most of their lives and were hired because of their roots in North American cities. Several are married to U.S. citizens, Saballos said, and have children who are U.S. citizens. Sixteen U.S. citizens are involved as dependents, she said.

For instance, Noel Corea in New York City has an American-born wife and a month-old child. Roberto Vargas has lived in the United States since he was 5, and has three teen-age children. He works for the embassy, Saballos said, but until recently worked for the consulate in San Francisco and was included on the list of those expelled.

Saballos said the consul in Santa Barbara, who was not named in the expulsion order but might be affected by it, is married to a U.S. Air Force captain.

Aura Beteta, consul general in San Francisco, said she would be leaving two teen-age children when she flew to Managua last night. Like several consular officials reached yesterday, Beteta deferred to higher-ranking officials for extensive reaction to the U.S. expulsion order.

"I don't think it's fair because we have not done anything wrong, we have not violated any law," she said. "But it's not what I think that matters."

Consul Leonor Arguello de Huper in New York described herself at 61 as "one of the oldest Sandinistas," and said her children and grandchildren are in Nicaragua. "I'm going to be given an opportunity to serve my country and my revolution in another way," she said. "Whether it is to go to the front and cook for the boys or do anything else, we are looking forward to going home."

Arguello declined to discuss the political significance of the U.S. action, except to say, "I think it's another mistake they're making."

Alexander Palacios, interviewed by telephone three hours before his plane was to depart, said he had not had time to talk with his son. Greta Palacios said she and her son, who plans to enter UCLA next fall, had not thought about the future.

"What I'm going to do is just wait for my husband and hope that relations between our countries will improve," she said. "My family will not be the only one affected. There will be many Nicaraguans here with no one to help them."

Consuls are charged with providing assistance to Nicaraguan nationals in their areas as well as issuing visas and promoting trade.