Kevin Federline has barred the couple's two children from watching Britney's Circus show.
After seeing her in action during rehearsals, K-Fed, 30, decided Sean Preston, three, and Jayden James, two, were a little too young for the raunchier parts.
So instead Britney, 27, treated her sons to a kiddie-friendly run-through of her 90-minute show at the New Orleans Arena.
The trio had a tearful goodbye as the boys were collected afterwards - and returned to K-Fed.
A source said: "It was great for Brit to have the children around.
"There is so much riding on the tour that she had worked herself up and her nerves were getting to her.
"Seeing the boys before her big night helped to relax her. She let them see most of her numbers in rehearsals, but the really sexy ones she left until the late-night run throughs when they had gone home."