Key work on the traditional ballad was undertaken in the late 19th century in Denmark by Svend Grundtvig and for England and Scotland by the Harvard professor Francis James Child. They attempted to record and classify all the known ballads and variants in their chosen regions.
Gaslighting is a form of manipulation that seeks to sow seeds of doubt in a targeted individual or members of a group, hoping to make targets question their own memory, perception, and sanity. Using persistent denial, misdirection, contradiction, and lying, it attempts to destabilize the target and delegitimize the target's belief.
If so, your partner may be using a form of abuse that mental health professionals call gaslighting. This term comes from the 1938 stage play Gas Light, in which a husband attempts to drive his wife crazy by dimming the lights (which were powered by gas) in their home.