02/22/2012 AT 01:00 PM EST
and wife Jennifer Garner
have baby No. 3 on the way any day now – but that's not the only project on Affleck's mind.
The actor, 39, founded the Eastern Congo Initiative in 2010 and recently got back from his eighth trip to the war-torn region. Affleck says it's his kids, Violet, 6 and Seraphina, 3, who inspire him to do good in the world.
"I got to a point in my life where I felt like I had been very fortunate," Affleck tells PEOPLE in an interview for the Feb. 27 issue, on newsstands now.
"And I wanted to do something more with my life than just make movies and try to make money. I wanted to do something that was important to me in other ways and would serve as an example to my kids."
Wednesday, Affleck launched a Facebook timeline
to share pictures and stories from his trips to Africa. His nonprofit helps support Congolese-led organizations helping to rebuild the region, from groups aiding former child soldiers to those supplying health care to the most vulnerable.
"The people there are working as hard as they can to make their lives better," says Affleck. "And that's inspiring."
As for his own kids, Affleck says he shows them where he's going on a map when he travels to Africa. Says the actor: "I tell them it's important to be involved in the world in ways that help others and not just yourself."