Green’s Dictionary of Slang

(US prison) used by Hisp. inmates for the new boyfriend/lover who takes one’s place while one is incarcerated.

1990		S. Morgan Homeboy 146: Jody was moniker all prisoners christened the anonymous lovers inevitably taken by their wives and sweethearts [...] The cholos call him Sancho.
2002		J. Lerner You Got Nothing Coming 145: Long after they have faded from the memories of girlfriends who have already faded into the arms of Jody or Sancho.