"a person who was living with the tenant as his or her wife or husband shall be treated as the tenant’s spouse, and a person who was living with the tenant as if they were civil partners shall be treated as the tenant's civil partner"

(s. 17(4) Housing Act 1988 http://www.legislation.gov.uk/ukpga/1988/50/part/I/chapter/I... )

(Interestingly, an identical provision in another act - but with only the wife/husband language, as this was before civil partnerships - was used by the courts to give a similar benefit to a surviving member of a gay couple, using the non-discrimination provisions of the Human Rights Act to interpret the provision broadly to include gay couples living as partners (Ghaidan v Godin-Mendoza)).