Aristotle, in his Ethics, argued that good legislators should pay more attention to friendship than to law. Common law, however, has trouble with friendship and has historically taken the view that agreements between friends are unenforceable for lack of intention to create legal relations. The roots of this presumption against amicable agreements lie in theology and antique ecclesiastical case law. Those sources are reviewed here and it is argued that seemingly progressive decisions that accord cohabiting friends legal recognition as spouses have the paradoxical effect of depriving them of contractual capacity. They join traditionally married couples in the ‘amity’ of the household which case law defines as an Alsatia outside of law. It is argued that such a consequence is both unintended and undesirable.