Urban, 43, worried that the time away would wreak havoc on their new union.
"Surely let's give it a few years so we've got some solidity, because this kind of thing could tear us apart," the country singer said Monday on "The Oprah Winfrey Show." "This could just destroy us."
But it was Kidman herself, plus a few close pals, who staged an intervention for Urban, who was hooked on cocaine and other substances.
"It was really a profound moment in so many ways," the crooner said of the intervention. "The way in which Nic handled that moment was just perfect ... Everything was just designed, I believe, for that moment to fuse us together."
It was, in fact, Urban's third time in rehab in eight years. "I had to make a decision which road I was going to take, once and for all," he said. "I'd been at that crossroads before and always taken the wrong road."
What was different this time?
"Love," he told Oprah Winfrey.
Urban left for rehab the same night as that intervention, he said. "I didn't care about anything else."
He gushed of his wife (and mother to their daughter Sunday Rose, nearly 2): "I look back now and realize Nic has taught me so much and brought so much into my life and opened my eyes in so many ways ... [This is] the best place I've ever been."
Actress Kidman also opened up on "Oprah" about their enduring romance. "I think marriage is about, every day, trying to make it better and working through things and when things are tough, saying, 'I'm going to come to you and talk,'" the "Rabbit Hole" star mused. "We're just very tight, and we stay really tight."
Both Australian, Kidman has really taken to their new life in Nashville, Tenn. "Some people like the much higher sort of more glamorous lifestyle," she said. "For us, we just prefer a much quieter, private [life]."
As for her favorite things to do with Sunday Rose, whom they sometimes call "Sunny"? Sharing her cappuccino foam -- and taking baths.
"I love her little shoulders, you know?" Kidman cooed. "She's in the bath, and I see those tiny little shoulders. Oprah, don't get me started!"
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