The verse your wife thinks is dirty is:

"I ain't gonna work for Maggie's brother no more.
No, I ain't gonna work for Maggie's brother no more.
Well, he hands you a nickel,
He hands you a dime,
He asks you with a grin
If you're havin' a good time,
Then he fines you every time you slam the door.
I ain't gonna work for Maggie's brother no more."

The verse is about a boss who pays next to nothing in wages and then expects you to be grateful that he's given you a job.

Sometimes a verse means just what it says it means. Maybe your wife has a dirty mind. (hehe)