Doctors' visits became like CIA missions, Bullock said, with decoys and dark cars. And the couple managed to arrange a bris, a Jewish circumcision ceremony, because they couldn't have the procedure done in a hospital without tipping off the media.
"I don't think we would have had that special an experience had our situation been anything other than the secret world of Louis that we lived in," Bullock said. "It allowed us to spend every waking moment with our little man."
It also meant fittings for Oscar dresses had to be done outside the home and that Bullock got little sleep while taking care of Louis without hired help.
"She really, really relies on close relatives and friends and she doesn't hire help -- they're the people who normally gossip," Shuter said.
Bullock has relied on them even more since her split last month from James after she learned of his alleged infidelities.
"She has been hiding with the baby since the scandal broke," People magazine senior editor David Caplan said. "She said that when she found out about Jesse's affairs, she grabbed Louis, she grabbed their stuff, and she left."
Bullock said, "All I remember is thinking, 'I need to get Louis out of here before the vultures descend.' I wasn't sure if I could go into deeper hiding than I had already been in, but again, that small group of friends and family made it their life to make sure we all had what we needed to heal and be safe and make sense out of all of it."
Still to be worked out are what role James will play in Louis' life.
James, who recently completed 30 days in rehab, told People, "The decision to let my wife end our marriage and continue the adoption of Louis on her own has been the hardest. The love I have for Louis cannot be put into words. Not having him around to love and to hold has left a huge hole in my heart."
Bullock, for her part, said, "I really don't know how our paths will intersect in the future, but the father I have known Jesse to be with all the kids is one that I hope Louis can experience one day, no matter how Jesse and I go on with our lives."
She added that James' children, regardless of what their relationship to her is "on paper" will continue to be a part of her and their brother's life.
Now that her secret is out, Bullock said she's looking forward to being like other proud moms: "Telling everyone I meet about the most beautiful man I know, including his poop schedule."
ABC News' Sheila Marikar contributed to this report.