02/28/2012 at 04:30 PM EST
As the Global Ambassador for the Avon Foundation, Reese Witherspoon
knows that in the U.S. and worldwide, one in three women will experience domestic violence in their lifetimes. As a mother, she wants her kids to know that, too.
"We talk about domestic violence and what that means," Witherspoon, 35, told PEOPLE Tuesday at the 2nd World Conference of Women's Shelters in Washington, D.C., about educating her own family
"Although the concept is somewhat foreign to them, they're starting to understand that this happens to families in our country and all throughout the world."
Witherspoon's two children – daughter Ava, 12, and son Deacon, 8 – have also talked with their mother about a recent public case: the felony assault
by Chris Brown on then-girlfriend Rihanna
in February 2009, after which he pleaded guilty
"My daughter knows what happened. My son knows as well," says the Oscar winner. "We talk about what is abuse. I think it's important to talk to our daughters – and our sons – in order to educate them at an early age about what's appropriate and what is absolutely not acceptable."
Luckily for Witherspoon, she's found herself in a happy relationship and marriage with husband Jim Toth
. The couple's first wedding anniversary is next month.
"I don't know what we're doing, but I'm very excited!" she says. "It happened so fast – it all went so quickly."