bidey in noun a common-law spouse or live in lover; a cohabitee originally and still mostly attested in North East Scotland, 20-. etymology: first element a diminutive of Scots bide ‘to reside, stay’ + English in; attested by SR and BW note:

This term can also be applied to the situation of living together without marriage: They two arenae merried – they’re just bidey-ins.