Disclaimer: I own nothing, please don't sue me! :)
Peter fought great battles; his skill with the blade was legendary. He had, on many an occasion, sacrificed his physical well being to protect his kingdom and his family. Peter treasured his role as protector, savior and father to all. But it was not Peter's skill as a soldier which endeared his subjects to him; it was his love.
Peter's love for his family and his country bound him to Narnia like none other before of after him. His title of High King was earned again and again through loving sacrifice, both physical and emotional. He had no idea that he would soon be called upon to make the greatest sacrifice at all. Not death, for it would have been easy to surrender to death if it would have saved his people. No, Peter was called upon to make the sacrifice of life; a life away from all he had known and loved. This sacrifice would be harder to bear than any physical ailment and would take longer to heal.
When Peter was ripped away from all he had grown to cherish his spirit broke along with his heart. He begged and pleaded to be allowed to return. He bargained and promised and cried. He implored Aslan to return him to his people but try as he might he was unable to plead his way back home. Peter, the sword and shield of his family and his country, despaired, and forgot the strength of love.
Ever the High King Peter put on a mask of fortitude. His siblings drew their strength from him and his example. He comforted Lucy as she cried and bandaged Edmund's fist when he could control his confusion and frustration no longer. When Susan smiled gently at him he dutifully ignored the sadness behind her eyes. But Peter, having forgotten love, was unable to smile.
When Lucy came to him one day claiming to have found Aslan Peter was overjoyed. He went immediately to meet her at the church, and when he had spoken to her it all made sense. Edmund joined them not ten minutes later and Peter watched as the fire in his eyes was rekindled. He wondered if Edmund and Lucy saw the same change in him. Susan declined their invitation to meet them at the church, but patiently listened as they described their finding to her later that night. She smiled and told them she was happy they had found Aslan, but that didn't change the fact that they were living in England and not in Narnia.
On the one year anniversary of his return to England Peter made the ultimate sacrifice; he accepted the loss of his friends, his country and his past life. Lucy and Edmund joined him at the cemetery and at his command they kneeled below an apple tree and prayed. Though they had no body and no casket, the tears which wet the ground that day left no doubt as to their pain. As they worked to overcome the events of the past year Peter raised his head and offered their pain unto Aslan, for he knew that their suffering was greater than any son of Adam or daughter of Eve could endure alone.
When they left the cemetery hours later the three children separated. Had anyone been close enough to see, they might have sworn that the golden haired boy had the shining eyes of a lion, and that each child looked somehow older than they had hours earlier.
Time moved forward, as it must, and Peter grew to appreciate this new and strange world. The taste of an apple was sweeter, the colors brighter, the wind cooler than before. With Aslan had come hope. Peter's strong façade melted away as his new life became easier to bear. Soon he began to smile again, and then to laugh. And eventually Peter was able to love again.
Years later, on his wedding day, Peter held the hand of his blushing bride and his smile was genuine. When he said 'I Do' the room was filled with golden light and, though each person felt it differently, peace and light and love filled the church and the hearts of everyone present. He looked to his siblings and all three of their faces were at peace. Lucy and Edmund turned her heads towards the aisle and, following their gaze, he rested his eyes upon the great lion from which the light was emanating. It was in that moment that he remembered how Aslan had made the greatest sacrifice of all. As Peter had sacrificed his life for those he loved, so Aslan had done before him.
When Aslan shook his mane Peter knew that he was blessed and loved. When he looked into the lion's eyes he was filled with such joy that he felt he would burst. Peter, the High King over all Kings, knew the true meaning of love, perhaps better than anyone whom had ever lived. And Peter also knew that great as was his love for his family, his wife and his country, Aslan's love was greater still.