Soul assassin

A woman who slowly but steadily dismantles her partner's self-esteem and joy in life through constant nagging and passive aggressiveness.
Soul assassins are immediately obvious to third parties, but conceal their dark intentions from their victim by slowly increasing the level of abuse. The victim builds up a stronger tolerance to abuse until it can eventually not bear the burden anymore. This kills the soul.
The reason for the soul assassin's behavior is the lack of being able to take responsibility for their own failures and needing to blame the fault on somebody else.