While they're calling it quits on their marriage, Gwen Stefani and Gavin Rossdale's main focus will continue to be on their kids.
"Their priority is making sure they maintain a safe and secure home for their children regardless of what's happening," a source close to Stefani tells PEOPLE. "When you're separated and have kids, you're much more emotionally invested."
The pair are parents to sons Kingston, 9; Zuma, who turns 7 this month; and Apollo, 17 months.
Adds the source: "Knowing how she is as a mom, her top priority is making sure her kids feel secure and comforted during the process."
PEOPLE confirmed Monday night that The Voice star, 45, and Rossdale, 49, had split, and "it's an amicable parting," says the source.
Another source tells PEOPLE that even though both stars have busy careers, "the kids always come first."
"This is not a family that mostly relies on nannies," the source says. "Gwen and Gavin are great parents and mostly handle school drop-offs and pick-ups themselves. Gavin is a jokester and often has the boys doubled over with laughter and Gwen is very nurturing. She often shows up to afternoon business meetings with Apollo napping in a baby carrier."
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The couple met 20 years ago when their bands, No Doubt and Bush, toured together, then said "I do" in 2002. They would have celebrated their 13th wedding anniversary next month.
"While the two of us have come to the mutual decision that we will no longer be partners in marriage, we remain partners in parenthood and are committed to jointly raising our three sons in a happy and healthy environment," the pair told PEOPLE in a statement.
Reporting by MELODY CHIU