In the interview, she reiterates that "this is a separation and I think that takes a lot of courage."
Adds the actress (who had planned to take daughter Coco, 6, Trick-or-Treating with Arquette, 39, this past weekend), "Whatever is supposed to happen will be the best thing for us."
Echoing sentiments from Arquette's first tell-all Howard Stern interview a few weeks ago, Cox, 46, said that she and Arquette have become different people after 11 years.
"Sometimes you just realize 'Wow, we actually have grown apart," she said.
As for that Stern interview -- which Arquette has said made Cox "pissed" -- she said she called Arquette a "kook" and said "it's not shocking and Howard Stern -- he loves him and I'm a fan of Howard Stern ... David is an entertainer and I'm sure the people who listen to the radio are entertained by his stories."
As Us Weekly previously reported, she said she is relying on BFF Jennifer Aniston to get her through it all.
"We just have fun, we laugh, we're inseparable and it's great," Cox says. "It's funny, a lot of really close friends are kind of going through this right now or like Jennifer [who] has gone through it. I don't know what's going on in the planets or what, but things are being shaken up and I don't know what's going to happen, but, yeah, Jennifer has been amazing for sure."
More on Wonderwall:
More on Us Weekly: