The 41-year-old actor appeared on Monday's episode of Marc Maron's WTF podcast, where he opened up about his relationship with Moore, 57.
The star noted that he doesn't "hang out" with his ex, but that the former couple is on "good" terms. "I make a really conscious effort to stay in touch with the girls," he added of Moore's daughters, Rumer, 31; Scout, 28; and Tallulah, 26.
“It was eight years,” he continued of his marriage to Demi. “Tallulah was eight or nine, she was the youngest. Rumer was 12 or 13 when we first started dating. ... When we were getting divorced, Tallulah was graduating high school.”
Moore met Kutcher in 2003 at a dinner party and they married in 2005, only to divorce in 2013.
“I was helping raise teenage girls through their adolescence,” Kutcher went on to say. “I love them. I’m never going to stop loving them and respecting them and honoring them and rooting for them to be successful in whatever they are pursuing.”
Moore shares the three girls with ex-husband Bruce Willis. “I think you try … but at the same time I am not their father," Kutcher noted of Willis, 64. "I was never trying to be their father. I always had respect and honored Bruce, and I think he’s a brilliant human being and a wonderful man.
"If they don’t want an engagement with me, I’m not going to force it upon them. But they all do and it’s great," Kutcher said.
Following his and Moore's split, Kutcher went on to marry his former "That '70s Show" castmate Mila Kunis, in 2015. They have two children: daughter Wyatt and son Dimitri.