05/04/2011 AT 09:00 AM EDT
Wedding bells aren't ringing yet for Cameron Diaz
, and they may never be. And she's cool with that.
Asked whether she thinks marriage is a dying institution, the actress tells Maxim
's June issue: "I do. I think we have to make our own rules. I don't think we should live our lives in relationships based off old traditions that don't suit our world any longer."
Diaz, 38, also talks marriage in the June issue of British Elle
. "I think a lot of people are married to people they're not romantic with any more," she says. "I just didn't ever marry anybody that I then had to get divorced from. We break up. We move on."
Diaz – who is No. 4 on Maxim
's 2011 Hot 100, behind No. 1 Rosie Huntington-Whiteley
– seems quite content in her current relationship
with New York Yankees slugger Alex Rodriguez. Without going into detail, she tells the magazine, "It's really awesome."
So, what makes a relationship successful? "Guys need women who challenge them and don't let them get away with their sh--," Diaz says. "Women, conversely, need to not be crazy bitches who blow up when their guys tell them something that scares them."
Diaz, who stars in the upcoming Bad Teacher
with her ex Justin Timberlake
, says she has a few girl crushes – "Mila Kunis
is a little hottie. Natalie Portman
is amazing … and the Victoria's Secret girls!"
But beauty is more than skin deep, she adds. "Women who know who they are and are confident are the sexiest. I don't find women who are looking for people's approval to be sexy. I mean, it's easy to seduce, but to be truly attractive, to bring people in and be sexy, I think that comes from the inside."