Sandra Bullock hasn’t just become an Oscar winner in 2010. She’s also become a mom, Hollywood’s unofficial best secret-keeper and, sadly, a divorcee.

The actress reveals her latest titles in the cover story of the new issue of People, on newsstands Friday. The front of the weekly shows her beaming with her new adopted son, Louis Bardot Bullock, and the confession that she and Jesse James are heading for divorce.

The adorable tot is 3 and 1/2 months old and the result of a four-year adoption process inspired by James’ daughter Sunny.

Louis was born in New Orleans, brought home quietly in January and named after Louis Armstrong because his proud mom heard “What a Wonderful World” in her head the moment she laid eyes on him.

“The first time I met Louis, it was like the whole outside world got quiet,” she says. “It was like he had always been a part of our lives.”

The timing—smack in the middle of awards season—was less than ideal, so the family agreed to keep the new addition out of the headlines until after Bullock picked up her haul of statuettes.

“I did not want him brought into a world that would not have been too sincere to him as I wanted,” she claims. “I wanted to be alone with him as long as I could, then we had to tell his story.”

But, it turns out, Bullock will be raising Louis alone, she also confessed. She’ll be finalizing the adoption as a single parent.

After the shocking revelation that her husband had been cheating on her, Bullock took her son and left the house as quickly as possible, “before the vultures descend.”

“Yes, I have filed for divorce,” she says. “I am sad and I am scared.”

James will remain in Louis’ life, however.

“I really don’t know how our paths will intersect in the future, but the father I have known Jesse to be…is one that I hope Louis can experience one day, no matter how Jesse and I go on with our lives,” she admits.

James echoes some of those thoughts—as well as hope for reconciliation—in a statement he released to People.

“I know in my heart that I can be the best father possible to my four children and the mate Sandy deserves, and realize that this is an incredible mountain to climb,” he says. “But I believe the steps I have taken in the last 30 days are the foundation to making this happen.”

Larry Hackett, managing editor of People, told the Today show that it was Bullock herself who came to them with the desire to share her big news. He said that, as far as her feelings about Jesse go, “there’s no anger. There’s sadness, obviously.”

“Maybe I needed this to happen so I could be the best mother to Louis,” Bullock says. “We wouldn’t know the sweet moments in life unless we had the pain. And painfully, I’m going to miss so much.”