ROCKER Jon Bon Jovi says his 13-year marriage has survived touring, groupies and fame because his wife Dorothea keeps him grounded.

"It's hard work, but my wife makes it easier. She's a karate instructor and incredibly independent," explains Bon Jovi, 40. "She's the mother of my kids and truly my best friend."

The star, whose new album Bounce was just released, lives in Red Bank, N.J., with Dorothea and their kids Stephanie Rose, 9, Jesse James Louis, 7, and 6-month-old Jacob Hurley.

They married in 1989, but have been together since high school.

"She's been there for me for the ups and the downs. She was there for me before there was an up," adds Bon Jovi, who also starred on Ally McBeal.

"She's the muse for all the syrupy ballads I write."