Paltrow is parent to daughter Apple and son Moses with ex-husband Chris Martin, while Falchuk shares daughter Isabella and son Brody with his ex-wife. Paltrow said she and Falchuk wanted to be considerate of their children.
"We each have two teenage children, whom we love very much," the star said. "We were just trying to be mindful and give them a little space, not move too quickly."
"Less merging originally, but now we're merged and it's great," she added.
Paltrow said Falchuk got to keep some of his stuff when he moved in. She agreed with host Jimmy Kimmel that her stuff is nicer, but complimented Falchuk's taste.
"He has good taste. He's got really nice clothes, and we put some chairs in there," Paltrow said.
Paltrow and Falchuk celebrated their first wedding anniversary last week. The couple spent the day at a beach on Long Island and shared a smiling selfie on Instagram.
"Year one, done," Paltrow wrote.
Paltrow and Falchuk recently collaborated on the Netflix series The Politician, which Falchuk co-created with Ryan Murphy and Ian Brennan. Paltrow confirmed Falchuk and Brennan wrote the character of Georgina Hobart for her.
"First it started with that I was inspiring the part and then by the end he was like, 'You have to do this TV show,'" she said.