At first glance, Scott Weiland seemed to be living down to his bad-boy image. Partying with friends at L.A.'s exclusive Buffalo Club last month, the lead singer of the hit '90s band Stone Temple Pilots—a man once called "the Robert Downey Jr. of rock and roll" because of his chronic substance abuse—had a bottle in one hand, his arm wrapped around a beautiful model. Except that now Weiland, 32, wasn't chugging tequila but Evian water, and the model was his wife, Mary Forsberg, 25. Though married only since May, they were celebrating an anniversary: the first year that Weiland has been continuously sober since his teens.

"People said it could never happen," says Weiland, who admits he shared their doubts. "I knew I needed to be sober for years. But I didn't want it enough."

"If you had asked me a year ago, I would have said, 'No way,' " says STP bass player Robert DeLeo. But now, says his guitarist brother Dean, "it's just nice to see the path that Scott's chosen for himself. I'm really happy for him. And his sobriety carries on to extracurricular activities, you know? Such as our little band."

The band, which folded in 1996 as a result of Weiland's repeated dalliances with alcohol, heroin and cocaine, is back with a vengeance. STP's 1999-album, No. 4, has gone gold, and on July 30 the band embarked on a nationwide tour with the Red Hot Chili Peppers. "Scott has never sounded better," says the band's manager Steve Stewart.

Yet Weiland sounds regretful as he traces the roots of his drug addiction. Raised in rural Chagrin Falls, Ohio, by his mother, Sharon, a real estate agent, and stepfather David Weiland, now a manager at Lockheed Martin, he started drinking casually at parties in the seventh grade, soon graduating to pot. "It was just playful experimentation," Weiland says. At 16, a year after the family moved to Huntington Beach, Calif., Weiland formed his first band and tried his first narcotic: cocaine. A six-week stint in drug rehab didn't cure him. Even after he teamed with the DeLeo brothers and drummer Eric Kretz to form Mighty Joe Young in the mid-'80s (they renamed themselves Stone Temple Pilots in 1992), Weiland's drug cravings intensified. "I had flirted with everything," he says. "But I hadn't found my thing yet."

That thing was heroin, which he tried for the first time while on tour in 1993. "I felt like it filled a hole that had always been there," says Weiland, but his erratic behavior, well-publicized drug busts and failed rehab stays alienated his bandmates, and they called it quits. "We didn't work for three years," says Dean DeLeo. "It wasn't about the band. It was about Scott being alive at the end of the week."

In October 1997, Weiland, who had been wed briefly at 27, ran into an old girlfriend, Mary Forsberg, at an L.A. rehab center. They moved in together, and soon she was sharing his heroin habit. Intermittently sober, he began recording with the band again last year. But after OD'ing on methadone last summer—his third probation violation since 1997—he was sentenced to a year in prison. "Scott's going to jail was the best thing that ever happened to us," says Forsberg, who kicked her own habit when he was sentenced. She was there to pick him up on Dec. 30,1999, when Weiland, having completed a drug rehab program behind bars, was paroled.

In mid-January—six months sober—Weiland proposed. And on May 21, at the Little Door restaurant in Hollywood, the couple wed. "I've known Scott for probably 15 years," recalls one guest, Dean DeLeo, "and this is the best man I've known in that time." Now awaiting the birth of their first child on Nov. 27, the Weilands curl up in their stylish two-bedroom apartment in L.A. and watch A Baby Story on the Learning Channel. Only last year the couple would have been partying till dawn. But both say they don't miss the bad old days. "Look," says Weiland, "no one goes to school to learn how to be a rock star. There's no class you can take for how drastic your life changes. You just hope you learn from your mistakes."

Mark Dagostino in Los Angeles