"We are all very tight and very close and very supportive of everyone," Arquette, 42, told reporters at an event last week at The House of Blues in Los Angeles.
But when asked whether he'd be a guest at her wedding, Arquette replied, "I doubt that."
Arquette, who has a 10-year-old daughter, Coco Arquette, with the "Friends" star, recently talked about their 2010 split.
"We just really dealt with it in a very sweet and honorable way. I don't know. We just love each other," Arquette said on Bravo's "Watch What Happens Live" Sunday. "Even though the relationship didn't work out, we wanted to still remain friends and treat each other with respect and have a great relationship for our daughter."
Added Arquette, "In the negotiating process of a divorce, we did it with a mindful head: 'What are you cool with?' 'OK, I'm cool with that, too.' There it is. There was no hair pulling."
Both have since moved on. Arquette welcomed a son, Charlie West, with fiancé Christina McLarty in April. In June, Cox announced her engagement to McDaid via Twitter.