"Thanks," Marek said, moving over to the chair to find that she was right. He wasn't at all surprised that she had known exactly what he was looking for; in that way, at least, nothing had changed. It gave him enough ... well, he didn't know what the word was, vigor maybe, or stubbornness ... to try one more time. He wasn't looking at her, had heard her footsteps move away, so he wasn't entirely sure she could hear him, but he said it anyway. "I just don't want this to end badly, that's all," he said. "Trust me, in this case I don't want to say 'I told you so'."
He wouldn't have said that they were growing apart, he would have stubbornly insisted that they would be fine, if she'd only just do what he usually did whenever she seemed likely to outgrow him - run to catch up. But this wasn't moving into a new flat, and it wasn't taking the Mark. He couldn't make her move to a new place emotionally if she wasn't going to get there herself.
So, he was done. He shrugged into his coat, stuck his hands in his pockets, and turned on the spot, Apparating away.