Bullock, 46, and Reynolds, 34, were both married when their 2009 big-screen comedy, "The Proposal," became a huge hit.
Internet gossip in recent weeks has suggested Bullock and Reynolds are now dating.
"I think there will be a collective sigh amongst women across the United States when I say he's not my lovah," People.com reported Bullock told "Today's" Al Roker on the red carpet before Sunday night's Golden Globes in Beverly Hills, Calif. "He's just an amazing friend for 10 years ... but I don't get his loving after dark."
The Oscar-winning actress went on to say the only man in her life right now is her 1-year-old adopted son, Louis.
"It's all I can handle," she said.