The Un-divorced

John Frost and his wife had been unhappily married for much of their 25 years together when his company relocated him in 2000. So when he moved from Virginia to Knoxville, Tenn., he left her behind.

The answer: neither. "After a few months," Mr. Frost said, "we both realized we liked it this way."

Technically, the two are married. They file joint tax returns; she's covered by his insurance. But they see each other just several times a year. "Since separating we get along better than we ever have," he said. "It's kind of nice."

And at 58, he sees no reason to divorce. Their children have grown and left home. He asked himself: Why bring in a bunch of lawyers? Why create rancor when there's nowhere to go but down?

"To tie a bow around it would only make it uglier," Mr. Frost said. "When people ask about my relationship status, I usually just say: 'It's complicated. I like my wife, I just can't live with her.' "

The term "trial separation" conjures a swift purgatory, something ducked into regretfully and escaped from with due speed, even if into that most conclusive of relationships, divorce. We understand the expeditious voyage from separation to divorce, the desire for a clear-cut ending that makes way for a clear-cut beginning. We hardly look askance at the miserably married or the exes who hurl epithets in divorce court.

But couples who stubbornly remain separated, sometimes for years? That leaves us dumbfounded. "I see it all the time," said Lynne Gold-Bikin, a divorce lawyer in Norristown, Pa., who is the chairman of the family law department at Weber Gallagher. She can cite a docket of cases of endless separation.

With one couple separated since 1989, the wife's perspective was, "We still get invited as Mr. and Mrs., we go to functions together, he still sends me cards," Ms. Gold-Bikin said. As for the husband, "He cared for her, he just didn't want to live with her."

But at his girlfriend's urging, he finally initiated divorce proceedings. Then he became ill and she began taking over his finances -- a bit too wifelike for him. "He said, enough of this, there's no reason to get divorced," Ms. Gold-Bikin recalled.

Among those who seem to have reached a similar conclusion is Warren Buffett, the wealthy chairman of Berkshire Hathaway. Mr. Buffett separated from his wife, Susan, in 1977 but remained married to her until her death in 2004. All the while, he lived with Astrid Menks; they married in 2006. The threesome remained close, even sending out holiday cards signed, "Warren, Susan and Astrid."

Also in the ranks of the un-divorced: the artist Willem de Kooning had been separated from his wife for 34 years when she died in 1989. Jann and Jane Wenner separated in 1995 after 28 years but are still married, despite Mr. Wenner's romantic relationship with a man.

Society is full of whispered scenarios in which spouses live apart, in different homes or in the same mega-apartment in order to silence gossip, avoid ugly divorce battles and maintain the status quo, however uneasy. In certain cases, the world assumes a couple is divorced and never learns otherwise until an obituary puts the record straight.

Separations are usually de facto, rarely pounded out in a contract, and family law is different state to state. But even long-estranged couples are irrefutably bound by contractual links on issues like taxes, pensions, Social Security and health care.

Divorce lawyers and marriage therapists say that for most couples, the motivation to remain married is financial. According to federal law, an ex qualifies for a share of a spouse's Social Security payment if the marriage lasts a decade. In the case of more amicable divorces, financial advisers and lawyers may urge a couple who have been married eight years to wait until the dependent spouse qualifies.

For others, a separation agreement may be negotiated so that a spouse keeps the other's insurance until he or she is old enough for Medicare. If one person has an existing condition, obtaining affordable health care coverage is often difficulty or impossible. The recession, with its real estate lows and health care expense highs, adds incentives to separate indefinitely.

Four years ago, Peggy Sanchez, 50, a Midwest resident, parted amicably from her husband, who has fibromyalgia.