lost 40 lbs. after her January 2012 lap-band surgery
, and now she's getting to be at peace with her figure.
"I'm not striving for perfection
. This has to be for the rest of my life," Wilson tells PEOPLE at the Lane Bryant 34th Street flagship grand opening in New York City.
"So with two kids, a hectic schedule and being a working mom, I fluctuate and that's ok. I'm not beating myself up for it. Every year I'm making more progress now – and that's my goal."
Though she falls victim to the occasion "snacking," the singer/TV reality star sticks to the treadmill, walking and thrice weekly weight training sessions with her sister, Wendy, for exercise.
"I want that muscle percentage to go up. It's only three days a week, but that's good," Wilson, 44, says. "I feel like that's a great message to send out."
The mother of Lola, 7½, and Luciana, 3½ (with husband Rob Bonfiglio), is also sending out a healthy message about body image to her daughters.
"I tell my daughters
, 'You have to love yourself,'" she says. "If I ever hear them put themselves down I tell them, 'Don’t say that. You have to say positive things about yourself because you are what you think you are.' "
"For me, I know I don't weigh 120 lbs., but I’m also not 500 lbs.," says Wilson. "I am who I am and I celebrate where I am when I'm there."