Denise Richards and John Stamos

The actor made the revelation on HOWARD STERN's satellite radio show last week (17MAY06), adding he ended the fling because he wasn't prepared to play dad to Richards' kids with Sheen.

He says, "It really kind of was the kid situation and what she's going through. It just wasn't the right time, you know. I barely did get out of that one! She was upset.

"She's a great mom and dating women with kids is tough."