Bullock revealed Wednesday she had adopted an infant boy named Louis in January and filed for divorce from James, her husband of nearly five years, last week.
The bombshell announcements were made exclusively to People magazine weeks after several women claimed they had sexual relationships with James during his marriage to the Oscar-winning actress.
"My whole life has been full of hard decisions," James said in a statement to People.com after the latest Bullock stories broke Wednesday.
"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 to words. Not having him around to love and to hold has left a huge hole in my heart," the statement said.
"Sandy is the love of my life, but considering the pain and devastation I have caused her, it would be selfish to not let her go. Right now it is time for me to beat this addiction that has taken two of the things I love the most in life. I have always taken great pride in proving people wrong.
"That time has come once again to show that I am not what everyone says I am. 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. But I believe that the steps I have taken in the last 30 days are the foundation for making this happen."
James said Bullock should not be blamed for things he has done.
"She has done no wrong. She played no part in any of this. She has been an amazing wife, mother, and best friend, for the over six years we have been together."
Bullock is also stepmother to James's three children from previous relationships.