Back when she was married to Tom Cruise, Kidman admits she used to lean on the Rock of Ages star, now 50, for support during public appearances.
"In those early years, it was like, 'I'm here and I'm clutching onto your arm and it all feels a little overwhelming and really strange,'" she tells the mag. "And I was shy. Deeply shy. I didn't feel comfortable at all. But I felt very comfortable at home."
After splitting from Cruise in 2001, Kidman settled down with fellow Aussie Keith Urban in 2006. When discussing the two men during her interview, Kidman admits that she was initially attracted to each star because she admired their confidence.
The actress says she has always appreciated "a bigger, stronger personality; that's what I've been drawn to. I need protection. Everyone wants to feel someone's got their back."
Urban -- with whom she has two daughters, Sunday, 4, and Faith, 22 months -- certainly gives her the support she needs. With his help, Kidman says she's been able to put some of her self-esteem issues behind her.
"He just gave me confidence through just being very kind to me and understanding me," Kidman explains. "Opening me up to trying things, my sexuality, those sorts of things."