"You and your secrets," said River teasingly, "You'll be the death of me!" She pushed lightly past the Doctor and walked across the console room to check the scanner. A flicker of sadness passed over the Doctor's face at the irony of her remark. But, as quickly as it came, it disappeared, and he transformed his demeanor back into the goofy, child-like man that she knew so well.
He studied his wife's finessed features, taking in every little detail. He wanted to burn her image into his memory; her laugh, the smell of her perfume- he wanted to memorize everything about her so that when it came time for her to make that last trip to the Library, he would still have a bit of her left to hold onto. He could never tire of looking at her.
"Sweetie you're staring again," said River without looking up from the console.
"Right, sorry," he said, blushing a bit. As she turned away to set the stabilizers, River suppressed a giggle at her husband's behavior. He was a bit like a gangly teenager taking a girl on a first date. She secretly loved it when he stared at her, because when he did he seemed so far away from all the pain and loss and suffering, and more toward the boyish wonder he had when he discovered a new planet, or found a bow tie he'd lost five years back.
Shaking himself from all the thoughts he did not want to think about tonight, the Doctor waltzed across the room, pressing buttons and pulling levers as he went.
"Well then, Doctor Song," he shouted over the screeching of the TARDIS parking break, "let's go see a billion stars!"
A broad grin spread across River's face as she slipped her hand into his. They opened the doors out to a brilliant sunset over a humble little village on Calderon Beta.