Miserable Relationships

I married a widow who had a grown-up daughter. My father, who visited us quite often, fell in love with my step daughter and married her. Hence, my father became my son-in-law, and my step-daughter became my mother. Some months later, my wife gave birth to a son, who became the brother in law of my father as well as my uncle.

The wife of my father, that is my step daughter, also had a son. Thereby, I got a brother and at the same time a grandson. My wife is my grandmother, since she is my mother's mother. Hence, I am my wife's husband and at the same time her step-grandson; in other words, I am my own grandfather.