"For me, it's about having a great partner to walk this life with," the star reveals in the October issue of Cosmopolitan (out Sept. 10).
The mother of two, who's been dating 26-year-old choreographer and dancer Beau "Casper" Smart since 2011, says, "I have my own high standards for what I want in a partner and how I want to be treated."
"I bring a lot to the table," she adds. "I'm not talking about material things but what I have to offer as a person – love and loyalty and all the things that make a good relationship."
It's hard to believe it but the 44-year-old, who's set to return to American Idol this season, admits that she battled insecurities for years and didn't start feeling good about herself until after giving birth to Max and Emme, her twins with singer Marc Anthony, in 2008.
Matthias Vriens-McGrath / Cosmopolitan
She credits her then-husband Anthony with helping her get over it.
"He kept telling me, 'You're the only one holding yourself back from reaching your full potential as a singer. You have to let go' … I was always so insecure and just kind of going along. Then I grew, little by little, and realized, wait a minute, this is not a fluke. I'm not a mistake – I work my ass off. And I know what I'm doing."