It's been a less-than-perfect autumn for the Simpson family: On Wednesday Oct. 24, Joe and Tina Simpson (parents to Jessica and Ashlee) confirmed to Us Weekly that they've filed for divorce after 34 years of marriage.

Still, their eldest daughter Jessica Simpson, 32, has so much to buoy her spirits in the midst of her mom and dad's split: An adorable new baby daughter (Maxwell Drew, 6 months), a devoted fiance Eric Johnson -- and slamming post-baby body, one she's painstakingly and healthily crafting step by step.

After gaining 70 pounds during her pregnancy, Simpson -- famously targeted for her weight ups and downs in the past -- is slimming down thanks to the Weight Watchers PointsPlus program and four-times-a-week training sessions with celebrity trainer Harley Pasternak.

"She's so focused and determined," her Weight Watchers leader Liz Josefsberg tells the new issue of Us Weekly, out now. "She's very brave to do this in a healthy, more realistic way."

Indeed, the designer and singer was honest and upfront about her challenge. "My body is not bouncing back like a supermodel," she recently admitted. "I'm just your everyday woman."

But trainer Pasternak marvels at his client's progress and determination. "In over 20 years, I've never seen as consistent a weight loss," he tells Us. "Jessica's right where she needs to be . . . She's gotten so much stronger."

And Simpson is loving the camaraderie with her Weight Watchers pals, too. "It's really encouraging to know we're all going through the same struggle," she says of her weekly weigh-ins.

For all of the details on Simpson's body struggle, her daily diet, workout techniques -- and how she fights the haters! -- pick up the new Us Weekly, on stands Friday, Oct. 26.