Story about a man in abusive relationship with his much younger wife.

It was horrible, Dan—she was stealing my body—crowding me out—making a prisoner of me

The man kills his wife in a burst of anger with a candlestick, and hides her body in the cellar, then goes insane, not before confessing to his friend, Dan.
Dan, who is the narrator, unable to bear the knowledge, shortly after visit the asylum and shoots his friend.

That's it. That's the story. Everything else is just ramblings of two unhinged middle aged individuals.