Sancho

[Tina]

Just like Don Quixotes sidekick, Sancho Panza, a Sancho is a lover that a woman has on the side - in addition to her spouse or significant other.

[Britney]

Name used by fellow inmates for the guy that is fucking your woman and whom your kids are calling daddy while you are in jail. Most likely the person you think is your best friend or hate the most. Used in a heckling manner.

[Little_Girl]

The other guy

[Sarah]

Spanish for the person who comes in your back door when youre at work, drinks your beer, watches your TV, and fs your wife.

(s-on-cho)

[PussyCat]

A man who has a continuing sexual relationship with a usually married woman who is not his wife and from whom he generally receives material support which comes from her clueless husband.
-see, pimp, man-whore, or jigglow

[Jessica]

I agree with all of the above definitions (which are basically the same), but thought it was interesting to note that instead of saying salut when someone sneezes, most of the guys I know say sancho instead, which I guess means that if you sneeze that means sancho is at your house with your lady.

[PussyCat]

the guy ur gurl is cheatin on u wit; sancha for the female version

[Little_Girl]

The Nickname for the man your girl is cheating on you.
Sancho Comes From Sideshow.

[Britney]

a filthy mexican/spanish cunt that breaks into your home and eats your food and fucks your wife and kids when your at work.

[Donald Trump]

A [Spanish] name for [a side] [boy] or man