Based on a Febobe plot bunny:  At some point after the Quest, Sam and Elrond spend time together, talking about what it was like to stand inside the core of Mount Doom with a friend and see him lose the battle of will to the Ring.

A blend of movie- and book-verse.

FINDING PEACE

As soon as Sam awoke, and was assured that he was alive, and not dreaming, he insisted on tottering to Frodo’s room. Once there, he simply refused to leave -- except for those times when the healers needed to examine him or change his dressings. As the days passed, the staff of healers acknowledged among themselves that Sam seemed to draw strength just from watching his master sleep, and seeing him cared for with respect and tenderness. Sam ate and drank whatever was brought to him, and tried to sort out the many tales he was hearing about battles and death, valor and great deeds, Ents and armies and the astounding new height of Frodo's cousins. He answered questions from Gandalf, Aragorn, Merry, and Pippin about what had happened in Mordor, and at the Mountain. But there was one event he could speak of only with shame, and one person, in particular, felt he understood why.

“There you are, Samwise,” said a gentle voice from the door. “I was told to come here if I wanted to speak with you.”

Sam looked up to see Elrond standing in the doorway. “You want to speak with me, sir?” he asked in amazement. He started to slide down from the big chair so he could bow properly.

“Stay seated, my friend,” Elrond smiled. He drew up a second chair and seated himself in front of Sam. “I know your feet are still painful. May I see them?”

Sam raised his feet for inspection, and Elrond took them into his lap.

“They don’t feel too bad anymore,” Sam said, a bit embarrassed. “Strider isn’t letting me walk around much.”

“Strider,” Elrond said with a smile, “is very wise. As are you, to listen to him. I trained him in healing myself.”

“Did you?” Sam asked. “He took care of us the best he could, after Weathertop, and Moria. And he comes every day to see Mr. Frodo, even though he’s going to be king and all.”

“I am glad to hear it,” Elrond said, massaging Sam’s feet gently. He saw the opening in the conversation he had hoped for. “Aragorn has told me he felt great guilt when he realized that you and Frodo had gone alone to Mordor, and he could no longer protect you.”

“But he couldn’t have done anything about that!” Sam protested. “Especially when Mr. Frodo was determined to go off, no matter what. Strider couldn’t have stopped him.”

“Indeed, he could have done no more than he did,” Elrond said quietly. “Nor could you, Samwise.”

“Sir?”

“At the Cracks of Doom...” Elrond saw Sam’s eyes fill with sudden tears. “You could have done no more than you did.”

“I should have been quicker, or stronger,” Sam burst out. “I... I should have...”

“Should have what?” Elrond asked. “Fought your master for the Ring? Forced him to give it up? I stood in the same spot as you, Samwise, long ago. In that place I, too, had to watch as a noble and courageous friend was overcome by the strength of the Ring.”

“You... and that Isildur? You spoke of that at the Council.”

“Yes, Isildur. If I had tried to take the Ring from him, he would have fought, and perhaps killed me. If I had taken It by force, he might have lost his sanity, and I would surely have lost mine.”

“Mr. Frodo, he... he wasn’t himself,” Sam sobbed. “But when It was gone...” he smiled through his tears. “He was my master again. He was free.”

“Like Aragorn, you could have done no more than you did,” Elrond repeated. “Indeed, you – and Frodo – did more than most believed anyone would, or could."

Sam looked at his master’s peaceful face and took a deep breath, feeling a weight lift from him. Frodo slept quietly, his wounds healing, and would wake no longer pulled apart by a war being fought for his heart and mind... a war no one else could see, or understand. He had followed Frodo to the end of all things, and was with him still.

"I lost Isildur to the Ring, but you did not lose Frodo.”

“No, sir," Sam said with a relieved smile. "Except for that one moment, when the Ring took over at last, I didn’t ever lose him. Gandalf said not to, and I never did.”

“Gandalf didn’t doubt you, nor did I,” Elrond said gently, He smiled at the hobbit. “Well done, Sam.”

“Thank you, sir,” Sam whispered.