The 51-year-old Bush frontman discussed his "painful" split from Stefani and their subsequent shared focus on their three children in an interview with The Sun published Sunday.
"[Divorce] was completely opposite to what I wanted," he told the publication. "But here we are ... Apart from death, I think divorce is one of the hardest, most painful things to go through."
Rossdale and Stefani split in August 2015 amid rumors the singer had cheated with their nanny. The couple were married nearly 13 years and share sons Kingston, 10, Zuma, 8, and Apollo, 2.
"The one thing -- the only good thing, because everything else is not good -- is we care about the children and it's about them," Rossdale said. "So we do everything to make this life change as seamless as possible."
"We had 20 years together and that in itself is pretty incredible," he added of Stefani. "It's a lifetime. I still think she's incredible. It was a lovely 20 years and we have three amazing children. There were a lot of positives, and with time they'll become more and more obvious."
Rossdale had shared similar sentiments about his kids in an interview with the Sunday Times in October. He said at the time that he's had "enough" of fan and media attention to his divorce and is simply focused on his children.
"It's like enough already. I've got to move on. Everyone has got to move on," the star said. "Somehow you have to put one foot after the other and make it happen."
"For me, it's just thinking about [my sons] and how to prioritize them," he added. "I have an incredible life with them, and that's what matters. You can't keep up with all the vitriol. Just don't get into all that."