Who is Wife from Sudden Fiction International: Sixty Short-short Stories and what is their importance?

The unnamed wife of Disappearing is significantly overweight at the beginning of the story. Her husband emotionally abuses her and browbeats her into sex. She takes swimming lessons and begins swimming laps daily to escape her life. After a time she loses weight, and everyone compliments her. She does not care, though; she is not swimming to lose weight. She wants to disappear from the world. She loses more weight, to the point that no one recognizes or even notices her anymore.