Lisa was still in her nightgown and robe, sipping a cappuccino in the kitchen of the Washington, D.C., brownstone she shared with her husband, Del, when he walked in and announced he wanted to live alone. They had been married for 21 years. “I didn’t know what had hit me,” Lisa, 55, recalls of that fall morning in 2005. “I wondered, Does he have a girlfriend? A boyfriend? I had no idea what was wrong.”

Although the couple’s relationship had been strained for a few months, Lisa simply assumed they were going through a rough patch. She attributed Del’s loss of interest in sex and his suddenly quick temper to stress from his high-pressure job as a financial analyst. “Del was so on edge that he would yell at me about every little thing—like a knife accidentally placed in the dishwasher with the point up,” says Lisa, a writer and a teacher. Still, she figured that things would soon return to normal.

For Del, the decision had been a long time coming. Increasingly restless within his marriage, he wondered whether it was holding him back from leading a more exciting life. “I knew the problem wasn’t Lisa—it was me,” he says. “And I felt I needed to work through my mixed emotions alone.”

To Lisa’s frustration, Del couldn’t articulate any of these concerns—all she knew was that he wanted a separation. She and Del took turns sleeping in the guest room for a few months until she moved into an apartment of her own. By January 2006, the couple had hired attorneys. Their home, which they had spent the previous seven years painstakingly renovating, was put up for sale Lisa felt “broken” without Del, who had helped her raise two children from her first marriage and supported her through the deaths of her parents and sister. “He understood me better than anyone,” she says. She tried to move on and began dating other men—to little avail. “I was still in love with my