Britney Spears and ex-husband Kevin Federline haven’t exactly been on the best of terms lately, and the singer’s former spouse is airing more dirty laundry in an upcoming TV interview.

The one-time Spears backup dancer gave an extensive interview to Australia’s “60 Minutes” that is set to air on Sunday.

“I was mortified for her, I really was,” says Federline of Spears’ conservatorship in a sneak peek at the episode.

READ MORE: Britney Spears’ Lawyer Claims Kevin Federline Is ‘Cyber-Bullying’ With ITV Interview And Videos

“I still feel bad for her,” Federline muses, but then explains the reason he didn’t help Spears escape from the restrictive conservatorship she was under for more than a decade was out of concern for their sons.

“The boys, the boys, the boys. I had to worry about them,” he says. “I couldn’t get involved.”

In another snippet from the interview, he reveals that Spears hasn’t seen their sons in quite awhile. “It’s been a few months since they’ve actually seen her,” he says.

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Encapsulating their two-year marriage, Federline adds, “It was amazing… until it wasn’t.”

The full interview is slated to air in Australia on Sunday, Sept. 4.