I was reminded that I wrote this by a plot point in the wonderful story "All the World's a Stage," by trustingHim17 on this site. Please, go read that instead.
Holmes paused, listening to the conversation on the other side of the door between Watson and his client. He didn't like being nosy when it came to Watson's privacy, but couldn't help himself.
"What are you getting at?" Watson demanded.
"Does he pay you?" asked the client bluntly.
"Pay me? Who?"
"Sherlock Holmes, of course. He calls you his colleague and you have spent these three days working on my case with him and yet I am only writing him a check. Does he pay you or should I give you a separate check?"
Watson cleared his throat. "No, sir, one check for Sherlock Holmes' fee that he has specified. I apologize for any confusion."
"And he pays you?" the client rudely continued.
"Mr. Harper, Sherlock Holmes may do whatever he likes with his money. I am only a friend."
"He described you as a colleague."
"I am both, sir."
"And yet Sherlock Holmes is a rich man while you are poor."
Holmes could hear the frown in Watson's voice as he replied, "You are misinformed, sir. I am not a poor man. I live well and have no wants. Give your charity to someone who needs it as both Holmes and I do. Good day, sir!"
Holmes stepped back as the door flung open and Watson stepped through. He said goodbye to his client and collected his fee. Then, he and Watson headed to the train station to go back to London. The ride was quiet and they sat in silence until in their own private compartment.
Finally, Watson sighed audibly. "I know you heard that, Holmes. I, well, I meant what I said. I don't envy your money and happily come with you because I am your friend, not any other reason."
"Watson… I appreciate your selflessness. I did think once that... well, it may yet still happen. You should know there's money set aside for your children, if you ever have any. And if you do not, the money is still yours, set aside for you in care of my brother, as are my own funds."
Watson said nothing, only watched out the window. Both he and Holmes were remembering his dear wife Mary, who had died suddenly while carrying Watson's child. It had devastated Watson, and it was a broken man who Holmes had returned home to find. His greatest comfort while the world thought he was dead was that Watson and Mary were safe and sound and happy in London. When he returned, he learned of her death and all his dreams about becoming a cherished uncle to the Watson children and surprising Mrs. Mary Watson with how sociable he could be fell away. There was no more Mrs. Watson, and no Watson children, only a lonely man who thought that everyone he loved had died.
"Thank you, Holmes," Watson eventually whispered. "Who knows? Maybe one day. I just can't, well, imagine loving anyone like I loved her. Maybe one day when her memory is not as fresh. But for now I only ever finding myself comparing every lady I meet, no matter how charming, with her."
"In the meantime, Watson, you know I would give you anything you asked of me, don't you? Anything you need and all you need to do is say so. I mean it, Watson. I haven't actively split my fees with you, no, but I don't think I've been remise…"
"You haven't been, Holmes," Watson assured him, cutting him off. "You're a generous friend and have always been from the start. I remember how when I first knew you, you'd put coins in my pocket when you thought I wasn't looking and knew I hadn't enough funds to eat with. You were a poor man, too, and you endeared yourself to me with your graciousness long before I had any idea of your genius."
Holmes' face colored. "I didn't know I was caught. You were so sickly, then… there was a time I truly feared losing you before we even got the chance to know each other well."
Watson sat back in his seat, knowing Holmes was uncomfortable with such a personal topic and wouldn't discuss it for long. It was enough to know Holmes was a true friend and cared deeply for him regardless of how it seemed at times.
Holmes looked at him inquisitively but said nothing. He hoped Watson knew he meant what he'd said: whatever Watson needed he would provide if he could. He couldn't bring Mary back, but he could be a good friend. And he would be.
Notes: Often, I write just for my own amusement. I knew even when I wrote this, a couple years ago now, that Holmes' and Watson's dialogue is off. By now, however, I've dealt with some of the same themes in other stories, and so this short little fella got put in the rejects doc instead of being edited and made into a proper story.