It occurred to Sakura fairly early on in the relationship that with Naruto's Sage powers and her usage of the Creation Rebirth technique, the odds of her dying before him were very high.
Of course this was the sad fact of all couplings throughout the history of mankind. Someone would always leave another behind. Everyone knew this, still no one knew for sure who would go first.
She would calculate the odds, she would eventually settle on it being closer to a near certainty rather than chance, and she would keep it to herself, letting it lie heavily on her mind.
It conflicted her for years.
When he was sick or wounded or simply feeling down, when the need to take of care of him was high, she passionately rejected the notion. She would not abandon him, ever.
Yet when she was heated by his embrace or simply warmed by his smile, when she truly considered the thought of watching or waiting for him die. She embraced the notion with all her heart.
She told him her thoughts eventually, or rather he managed to pry it from her when she happened to be in one of her darker moods.
Nartuo paused for a moment to reflect on Sakura's thoughts and she found herself increasingly curious of his opinion. She was sure neither one of them would've wanted to be without each other. So what would he say?
He said, "don't worry about it. I don't think you have a choice here."
She was silent, taken aback. Was he making a philosophical point? Theological? Common sense? Was she like the foolish men of The Leaf's old tales, men attempting to swim upstream against the current of fate.
He took her right hand in his and traced the ring on her finger.
"I promised to take care of you for the rest of your life. And I will."
He let the implication hang in the air filling the room.
It comes to her in a wave, a flash-flood of guilt anxiety and pride. Her husband wasn't being particularly profound he was just being hard-headed! She opened her mouth, intent on challenging him, intent on setting the record straight.
She was disarmed however by his chuckle.
"Sakura-chan I know if you wanted to beat the odds you would..."
He caught her gaze. "But let me win this one OK? Let me win this fight."
Immediately she closed her eyes, she draws in a deep breath and then she let it go. Her worries went with it. Sakura opened her eyes and stared at Naruto for quite some time. She wondered briefly if there was a phrase to describe having the feeling of love at first sight with a person you'd been married to for years now.
"Alright" she said softly, delicately. It dawns on her that this was perhaps the first time she'd ever felt happy to concede an argument to anyone.
"Okay, let's just enjoy us for now." Naruto grinned warmly, carelessly.
Let him win? No there was no winning this kind of argument with this kind of hardheaded idiot. A loveable idiot who never backed down on his word.
She kissed him, because well as they say to the victor goes the spoils.