I read a short story online several years ago (between 2008 and 2016) that dealt with the discovery of nanotech based immortality and a man's search for his wife through the life of the universe.
The story starts on Earth with the man and woman touring the countryside on bicycles. One of their bicycles breaks and they end up in a small town to get it repaired. The repairs are affected by a nano-fabricator and this leads to the couple wondering if the same technology could be used to heal people.
The story skips ahead to the couple on top of a skyscraper to demo the nano-tech being used to heal a monkey. Somehow the demo fails, and the dead monkey ends up falling from the roof to the ground below. The scene closes with the monkey coming back to life.
Skip forward again, people have taken the nano-treatment and are in a rebellion on Earth. Many of them make it to space and take a ship to escape into the cosmos. An effect of the nano-tech allows people to change their physical form, and the man and woman are in space covering the escape ship's retreat. The woman gets near hit with a missile and is knocked away into deep space, while the man boards the escape craft and leaves the solar system.
The bulk of the story skips through the future history following the exploits of the man. While he is constantly searching for his lost wife, he has several different adventures, some of which are:
- The man takes the form of a pinecone and creates seed clones of himself that are scattered to space
- The man creates a physical copy of his wife and raises her as his daughter. Although she is similar to his lost wife, it isn't the same for the man and they go separate ways.
- The man encounters one of his clones that has created a party ship
The end of the story culminates at the end of the universe. Humanity has created a portal that sends everyone who enters into their own personal universe. The man waits here hoping to find his wife, as all people are coming here to enter the portal, but she never arrives. So finally, the man enters the portal and recreates the original universe just before the bicycle breaks. The man and woman go down a different route that leads to the nano-immortality never being invented and them not being separated.
