No, well, it would be if she had acquiesed to the idea if he had brought it up.
What you got here is a classic case of "buyers remorse," seriously. She's afraid SHE fucked up the relationship.
I'm just saying, from a woman's perspective, thinking about how I might feel in a similar situation. When a woman says "leave it alone" that's serious, because it means EXACTLY the same thing as when a man says it. It means drop it.
Think about it, usually women talk shit to death. What do you think it means when a woman DOESN'T want to talk about something?