The last time he saw her, she was kissing him. A perfect version of himself, wearing a blue suit. She didn't even take a second look at him. And he took his long last glance at her. A voice in his head told him, Run. It's over. So he did. He ran, and he never really stopped.
"But the Doctor's still you," she had said earnestly. She had tears springing into her eyes and ready to spill with the next word.
"And I'm him," he'd said, gesturing towards his metacrisis twin. But he knew that no matter how much Rose loved his other self, he would never feel it. Because that other version of him was perfect. And human. And made for Rose. But the real him was not.
Walking away with a heavy heart, he stepped into the TARDIS and set its course. He had no idea where he would go, he just knew it was anywhere but there. Never again. He would never see her again.
He saw her on the little screen, running for the TARDIS. He hit the flight lever, and watched her fade away. I'm sorry Rose. I am so, so sorry, he thought.
His last words to her. "Does it need saying?" It did. And he'd wished he had said it. But could it be said. No. And it was breaking his hearts.