Mary Koenig was having a blast Sept. 9, 2001, when Rescue Five, her husband Gerry’s Staten Island firehouse, held its annual picnic. Kids ran wild while adults tossed back beers and danced to the radio. Gerry’s close friend John Bergin was there, recruiting fellow firefighters to help the Koenigs build their dream house, a cabin two hours north of New York City. “John was an organizer,” Koenig recalls. “He thought it would be great to get Rescue Five up there.”

Two days later, on Sept. 11, their world came crashing down: Bergin, 39, and 10 other members of the fire company died in the collapse of the Twin Towers. Gerry Koenig, 43, was off-duty that morning—he rushed to Ground Zero after the towers fell—and his wife was grateful he’d survived. She had no idea then that their marriage would not. Following an old FDNY tradition of firefighters taking care of the families of fallen comrades, Gerry served as “liaison” to Bergin’s widow, Madeline, and her three children. He managed their finances, took them shopping and dined with them. In fact he spent almost all his free time with the Bergins, leaving his own wife and two sons to cope on their own. When Mary Koenig, 39, complained, “he told me he loved me and asked me to understand he really felt the need to be there,” she says. But the firehouse buzzed with rumors of an affair. Then in April 2002, Gerry confessed. “He said, ‘We’re more than just friends,’ ” says Koenig. “That’s pretty much how my marriage ended.”

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She’s not the only one. According to one top FDNY official, “as many as eight” firefighters have left their wives for women who are among the 200-plus widows of firefighters killed in the terrorist attack. Those numbers have led the firefighters union, psychologists and wounded wives like Koenig to question the wisdom of allowing untrained firefighters to serve as de facto counselors. “We knew this was going to happen,” says Rudy Sanfilippo of the Uniformed Firefighters Association. “You take firemen who aren’t even trained to [counsel] over a normal line-of-duty death, add the fact that the 9/11 situation was 10 times harder, and it’s a formula for disaster.” But former New York City fire commissioner Thomas Von Essen, who headed the department on 9/11, defends the practice. Firefighters who stepped up to help “were picking up kids from ball games, helping with renovations and repairs,” he says. “They weren’t sitting around drinking wine with the widows.”

While the FDNY won’t comment on firefighters’ relationships, a spokesman does point out that since 9/11, the department has expanded its staff of licensed counselors and psychologists from a dozen to more than 300. Counselors who worked with survivors of the Oklahoma City bombing had warned that the FDNY might see residual psychological effects in its ranks after 9/11. Among them was compassion fatigue—when caregivers experience a kind of secondary posttraumatic stress that can play havoc with relationships. “As rescuers we give ourselves; sometimes we give ourselves away,” says Jack Poe, chaplain of the Oklahoma City police department, a Baptist minister who worked with bombing survivors. “It almost cost me my marriage. When you put one person with another person of the opposite sex, and they spend that much time together, there’s no way there’s not going to be some bonding. ” Even if the intimacy is merely emotional, he adds, “that can be just as devastating as a sexual relationship.”

Gerry Koenig, for his part, refuses to blame his domestic misadventures on 9/11. “I was in a marriage that wasn’t working,” he told the Staten Island Advance. He and Mary met in 1982 at a restaurant where she was waitressing, married in 1990 and have two sons—Ryan, now 16, and Matthew, 13. The Koenigs separated at least once, in 2000, when Gerry went into a tailspin after being diagnosed with melanoma (he’s now cancer-free). “But we made a pact that divorce shouldn’t be an option,” says Mary, a former clothing-store manager now unemployed. Gerry also made a pact with John Bergin: Should anything happen to one of them, the other would take care of the surviving family. Some 9/11 widows say they couldn’t have coped without their husbands’ former colleagues. “There were nights where I’d call the firehouse and cry, and they cried with me,” says Jeanette Schardt, a mother of three small boys whose husband, John, of Brooklyn’s Engine 201, died in the attack. “But there’s an ethic,” she adds: ‘ “You don’t mess with your brother’s wife.’ ” Madeline Bergin, 42, a teacher, says the loss of her husband is an open wound. “There’s not a day that goes by that I don’t feel a knot in my stomach,” she told the Advance. “But then I wonder…should I wear black the rest of my life?”

Mary Koenig also questions how she’s supposed to go on. For now she’s lobbying the FDNY for a new rule that forces mandatory posttrauma counseling for firefighters. But what she wants most no new regulation can provide. “I wish,” she says simply, “my life were like it was when he loved me.”