Side Track

Mistress. A variation of ,"Side Piece."

She wants to be his wife, but all she can hope for is to be his side track.

Wrong side of the tracks

n. the poor, seedy, low-rent part of a town or city, especially characterized by crime, drugs, minority/immigrant populations, and poverty.

c.f. dog town, projects, ghetto, hood rat, reservoir dog

born on the wrong side of the tracks

To start out life with every disadvantage

Coming from nothing

Fighting for survival

Broke

Because Dick was born on the wrong side of the tracks he hates the world and everyone in it