Noun
A marriage in which the partners decide not to have children, and to reserve the right to divorce amicably with mutual consent.
(social history, anthropology) A conception of marriage where complicity, communication and support between spouses are considered important, rather than purely material questions of inheritance etc.
Source: en.wiktionary.orgBoth Edgeworth and Austen argue that women are crucial to the development of the nation; moreover, they portray women as rational beings who should choose companionate marriage. Source: Internet
Kaplan, "Wild Nights", 35. For example, Wollstonecraft advises her readers to "calmly let passion subside into friendship" in the ideal companionate marriage (that is, in the ideal of a love-based marriage that was developing at the time). Source: Internet