Confusion

A psychiatrist visited a California mental institution and asked a patient,
"How did you get here? What was the nature of your illness?"
He got this reply...
"Well, it all started when I got married and I guess I should never have done
it. I got hitched to a widow with a grown daughter who then became my
stepdaughter. My daddy came to visit us; fell in love with my lovely
stepdaughter, then married her. And so my stepdaughter was now my stepmother.
Soon, my wife had a son who was, of course, my daddy's brother-in-law since he
is the half-brother of my stepdaughter, who is now, of course, my daddy's wife.
So, as I told you, when my stepdaughter married my daddy, she was at once my
stepmother! Now, since my new son is brother to my stepmother, he also became my
uncle. As you know, my wife is my step-grandmother since she is my stepmother's
mother. Don't forget that my stepmother is my stepdaughter. Remember, too, that
I am my wife's grandson. But hold on just a few minutes more. You see, since I'm
married to my step-grandmother, I am not only the wife's grandson and her hubby,
but I am also my own grandfather. Now can you understand how I got put in this
place?"