Rather than heaping blame on Arquette, who Cox has previously said behaved like a child in their relationship, the actress says a lot of their problems had to do with her own issues.
"The thing is, when you get older, it's more about compatibility than it is about love," she tells the mag. "I think it's more about needing just a kind of peace and stillness. I'm kind of all over the place, and I need grounding. I want to be calm. I want to change a lot. I want to live not outside but inside. It's nothing with David; it's just what I'm searching for."
While she carefully parses her words, it doesn't sound promising that the pair will reconcile in the near future.
"I don't know what's going to happen, but I don't think he'll be doing more Howard Stern any time soon. He's not out to harm. But I'm his biggest protector. I can't help it," Cox says.
Still, Cox says she isn't itching to hit the town and revisit the dating scene. Though we think she and the Aniston would make a fearsome twosome out on the strip, Cox says she doesn't know the first thing about getting lucky these days.
"I have no desire right now," she admits. "I'm not saying never. It just seems weird. I don't even know how that would happen or how you meet people. I really don't like to go out. I'm not great at small talk. I like to go to dinner with people. I don't like to go to parties. There's a sign on my forehead: EXITING SOCIAL LIFE, ENTERING INTO ISOLATION."
For the whole interview and behind-the-scenes footage of the cover shoot, head over to HarpersBazaar.com.