Why did Aksionov think of killing himself in “God Sees the Truth, But Waits”?

“God Sees the Truth, But Waits” is the story of a man unjustly accused of murder, who is then tried, convicted, and sentenced to prison in the harsh climate of Sibera. Ivan Dmitrich Aksionov copes as best he can, but the years take their toll.
After 26 years, a new group of prisoners are transferred there. Among them is Makar Semyonich, who is from the same part of Russia and is familiar with Aksionov’s story. As they discuss it and Aksionov tells that the murder weapon was planted in his room, Makar makes a statement that convinces Aksionov that he was the person who actually committed the murder—he knows that Aksionov’s bag, where the knife was found, was under his head while he slept.
The realization that he has met the true murderer nearly destroys Aksionov. All that he has missed out on flashes before him, such as not seeing his children grow up. He has grown old before his time during these decades of imprisonment. When he thought of it all, he was so wretched that he considered killing himself.