The walls of the parallel worlds had opened once again, and he was back. He stepped out of the TARDIS, closing the door behind him, as always.
He remembered what memories this beach held.
"And here you are, living a life day after day...The one adventure I can never have."
He looked at Rose.
"...(crying) Am I ever going to see you again?"
"You can't." he watched her cry brokenhearted.
"What are you going to do?" she whimpered.
"I've got the TARDIS. Same old life. The last of the Time Lords."
"...On your own?"
The doctor nodded.
Everything they had done together. Everything they shared. Everything he lost. And there he stood. A new man with old memories.
Davros spoke, "The Doctor. The man who keeps running, never looking back because he dare not, out of shame."
The wind blew his hair aside as he walked to the edge of the water. Waves crashing over rocks in the distance. The rush of the ocean. Rising over him.
The last time he was here..there was another him. And when Rose asked them both how their sentence was going to end, he purposely gave his other self the chance to tell Rose those three words.
"I love you," he whispered.
The words she had craved more than ever before. She took him into her embrace as the Doctor watched. One adventure he truly could never have.
Everything was going to be okay. Rose had him and he finally had Rose.
He left them. To a promised life. To grow old.
"Together."
The Doctor had regenerated and they wouldn't recognize him. They've started their new life, (probably) doing so well..he just didn't want to interfere. But he could visit. He was going to see Rose.