term:

Extreme Cruelty

extreme cruelty n

: behavior toward a spouse that involves physical violence or threats thereof, acts calculated to destroy the peace of mind or health of the spouse, or acts destructive of the purpose of the marriage
;also
: a ground for divorce based on a spouse's extreme cruelty

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.