This is gorgeous and heartbreaking, and your voices are perfect.

This -

“She’s happy, Donna,” he insists, conviction in his voice, the smile gone from his face. “She doesn’t need me.”

He sounds desperate, as though Donna’s belief in Rose’s happiness is absolutely imperative to the functioning of the universe. Donna wonders if they’re still talking about Rose.

“Of course she is,” she says gently.
- made me want to cry, it's so exquisitely in character for both of them.