10/29/2007 at 01:00 AM EDT
While all eyes have been on Jennifer Lopez
, and her is-she-or-isn't-she waistline, her husband of three years has stood by, quiet and protective. During a stop on their tour in Chicago Oct. 14, singing her new song "Hold It Don't Drop It," Lopez, 38, suddenly started laughing. "I forgot the freaking words," she told the audience. No matter; soon after, Anthony, 39, joined her onstage to sing duets, rubbing her arm and quietly reminding her of what does matter. "There's such unity," says Leon Ichaso, who directed the couple in El Cantante
, a film about the salsa singer Héctor Lavoe that allowed them to tap their shared background (both are of Puerto Rican descent)—and, with a no-frills 33-day shoot, their work ethic. Adds her longtime trainer Gunnar Peterson: "She seems very content and safe and protected. She glows from life."
That life together—spent mostly at their Long Island home—is a far cry from her paparazzi-chased days with ex-boyfriend Sean "Diddy
" Combs and former fiancé Ben Affleck
. And it's largely due to Anthony's influence. One of the biggest salsa stars in the world, the two-time Grammy and two-time Latin Grammy winner has sold 7 million CDs in the U.S. and regularly fills arenas. But he's fiercely protective of his private life. If he and Lopez are expecting, their tight-lipped stance is nothing new: After they wed in June 2004, they didn't publicly acknowledge their marriage for another eight months. Anthony also won't hesitate to walk out of an interview if he finds a question intrusive. That old-school machismo brings Lopez "peace," says David Naranjo, a Miami-based media executive who has known both singers for years. "When she walks into a room, she can be the wife of Marc Anthony."
And when they add to their family, Anthony is ready to play Daddy. "Changing diapers, you really feel you're accomplishing something," the father of three told PEOPLE in '99. His wife would agree. "Career is very important for Jennifer," says Naranjo, "but family is more important. She and Marc are soulmates. They each finally found the right one."