Federline, who has two kids each with Jackson and Spears, was granted sole custody of his toddler sons with Spears until further notice.
Jackson told Usmagazine.com Spears' children haven't seen their mother since a judge yanked her visitation rights three weeks ago.
"They're babies, you know, they don't really know," Jackson said. "Of course, all kids say, 'mama,' but they don't really know (where she is)."
Jackson claimed she is helping Federline and his nanny out with his kids by Spears.
"They have a lot of positive people around them, so they're good," Jackson said. "The kids all spend a lot of time together, but I'm not trying to take anybody's place."
Jackson said she made a choice to keep things civil with the father of her children after they split up.
"It could have gone really bad and we could have become enemies," she told Usmagazine.com. "I don't have time for that. Life is way too short, and we're not promised tomorrow, so I don't want to go out and have bad feelings with anybody."