The pair slept together in 2002 when the Pop Idol runner-up was just 17.
"When I look at it now, it's gross, disgusting," Price told Piers Morgan's Life Stories.
"It's terrible - I was still young, I was pregnant, I didn't have the dad about and I still wanted to be loved. It was wrong when I look back."
The star added that she struggled to deal with son Harvey's disabilities when he was first born.
"You're told your child is blind, then you're called the mother from hell," she added.
"I knew people were thinking, 'It's her fault he's like that'. It's not easy. He's challenging. But I wouldn't change it for anything."