01/28/2014 at 08:00 AM EST
has mellowed out a bit when it comes to rigorous exercise. But old habits die hard – and she admits to being conflicted about letting go of the drive to look perfect.
"I've got an athletic body, I've worked out my whole life and I've been incredibly disciplined when I needed to be," the singer and American Idol
judge, 44, tells British Glamour
's March issue, on newsstands Feb. 3. "Now I'm just a little bit more relaxed in that area. I feel like this is who I am. But it's also hard to shed that old skin."
Lopez says how she looks is always on her mind.
"Mentally, I'm always thinking about it," she says. "I'm OK looking this way, but at the same time that very ambitious, determined girl inside me is like, 'Come on, let's be in the best shape ever and really show everybody.' Then the other side of me thinks: 'Let's just relax on the beach chair.' "
She also admits to being practically repulsed by the very idea of overeating. "I'm not one to overindulge," she says. "It doesn't make me feel good. Some people find it comforting to sit down and eat a whole pint of Häagen-Dazs, but honestly that would make me throw up. I don't think I've ever eaten that much."
On the subject of relationships, Lopez, who's dating Casper Smart,
says she likes a little turbulence in her love life, though she also wants stability. As long as the scales tip toward the plus side, she's good with it.
"The dream is to have a balance where you feel you could relinquish control from time to time and still be taken care of," she says. "What you want to do has to be respected. It's about finding a relationship that has enough good stuff to outweigh the bad, because nobody's perfect right? But without the spark that conflict brings, life would be so boring. I want a bit of chaos in a relationship, but I also want a bit of safety and order."
She adds: "It's taken me a long time to get to this place, but I've learned that I don't ever want to go against my own integrity in a relationship. If something doesn't feel right to me or makes me feel uncomfortable, I don't want to go along with it – and sometimes as women we do that. But I won't accept it any more."