@yanawrotethat I know one story that perfectly fits the description of what you’re looking for, and that story is H & V: The Smoke that Separates Us by @Res. Now, this is a fairly new (and underrated) story and a very interesting one in many ways. One thing that it does that makes it stand out from most other stories in my opinion is its well-written dialogue. It’ll keep you invested in the plot throughout the story, at least for me it did, anyway.
Anyways, without spoiling anything, the main character is a middle-aged man named David. In the story, you’ll follow and uncover his deep, internal struggles after he quits smoking. It’s some very interesting stuff. Here’s more about the story directly from the author if you’re interested:
I’d definitely give this one a read if you’re looking for stories with the description in your post. 