"Apparently she went and signed papers yesterday around noon," Bonaduce said Tuesday on KLSX-FM's "The Adam Carolla Show."
"I really don't want a divorce. I love her," he said.
Bonaduce, 47, said he received an e-mail Tuesday from her attorney offering phone numbers for lawyers.
Gretchen Bonaduce couldn't immediately be reached for comment. Her telephone number was unlisted.
Bonaduce said his wife had been talking about breaking up for several months and he held out little hope for reconciliation. "There's no fight. Nobody's mad at anybody at my house," he said.
"It's been months of 'You know, I think we'd be happier apart. I'm not happy, Danny.' But thing is, she has been friendly, and helpful," Bonaduce said.
It is Bonaduce's second marriage. The couple have two children.
The former child star of TV's "The Partridge Family" starred with his wife in "Breaking Bonaduce," which detailed his efforts to repair his relationship and recover from alcohol and other problems. The show aired on Viacom International Inc.'s VH1 channel.