If ur placing blame on him share some of it with her too. When he tried to tell her she stopped him cuz she didn’t wanna know since she had already decided to leave him.
Well all she needed was the truth and she got it. He didn't tell her anything, she knew nothing. So ofc she'd be pissed and would want to leave. So again, we're coming to the conclusion that it was lack of communication.
The prince is at fault because he didn't explain it to her. Like why are you so secretive? This screams lack of communication.