Though the couple has been living together since 2011 and engaged since 2012, marriage is "different," Theroux told People.
"It does feel different," the 46-year-old actor told the magazine.
"I'm very happy," he added. "It's nice to be able to look down and see a new piece of jewelry on my finger."
The couple wed in a secret ceremony Aug. 5 in their home in Los Angeles.
Asked how she managed to keep the big day a secret, Aniston told ABC News, "Where there is a will, there is a way."
Guests were told they were coming to Theroux’s birthday party, "and it was," Aniston, 46, explained.
The couple recently returned from their honeymoon in Bora Bora.