12/19/2011 at 12:00 PM EST
and Kevin Federline
have experienced their share of ups and downs since the pop star filed for divorce
But five years later, Federline, 33, says his newly engaged ex
, Spears, 30, is "in a good place."
"She's happy," the former backup dancer and new dad
, who is currently dating longtime girlfriend Victoria Prince, told Australia's TV Week
magazine. "She's doing really well ... [The engagement] is a good step in the right direction. I'm totally happy for her."
Federline, who says that his sons Preston, 6, and Jayden, 5, are doing well in school under Spears's care, adds that his ex's new fiancé Jason Trawick will be a welcome addition to the clan.
"I think he's a great guy," Federline says. "The kids speak highly of him. Her family loves him."
The father of five says it tore his "heart to pieces" watching Spears struggle so publicly
a few years ago, but he's grateful that the "dramatic, depressing stage" of his life is done.
"It was tough," he says. "I'm so glad it's over and I get to leave it behind."