The question is not sharing, but "co-habiting" as defined by SW. Co-habiting means sharing expenses, sexual relationships, socialising together, etc. .
Yes, I see MM's point too, especially when it comes to same-sex relationships. Say, if 2 men lived together as a couple would SW immediatly assume that or would they treat a claim from one or both as from two singles chaps sharing a flat?!
The legislation for aggregating means for Supplementary Welfare Allowance specifically refers to "a man and woman who are not married to each other but who are cohabiting as husband and wife" so there is no legislative basis to treat same-sex couples as a couple...reverse discrimination?!
Not sure what it is for other Social Welfare Schemes.
(Social Welfare Consolidation Act 2005, Secton 196).
Hmmmm..... very interesting that! Would love to see a test case taken!