Consensual union

June 15th, 2019 by

Consensual union

Consensual unions are popular around the world. What are they and what are their foundations?

If we were to browse our mother tongue to find some alternative to a word (deriving from French) consensual, we would probably choose a term: „unofficial marriage”. The consensual union is a relationship which seems to be like a marriage but, in fact, is not. Let’s have a closer look.


A consensual union has long been studied by academic researchers and has been defined in a number of ways. We do not wish to invoke all these definitions but let’s focus on what they have in common. What they have in common is the fact that people live together. If lovers live together but are not married, they form a consensual union (conhabitare in French means live). This is what sociologists jointly agree with. Disputes arise when other features of the consensual union are taken into account. The most renowned definition, suggested by Jan Trost, a Swedish researcher, in 1979 says:

a consensual union entails two persons of various sex, who live together for a long time, who run a joint household and who have sexual intercourse.

This definition is however imperfect because it does not specify the period of time in which partners live together. One of the Polish researchers, Wojciech Chechliński, filled the gap with a statement: „a man and woman must spend all weekends together within four months together or spend at least four-five nights a week together in the space of least three months”. Other definitions emphasize lack of legal grounds for consensual relationship (for more about legal aspects of formal and informal partnerships, please read here: ).

Nature of consensual union

Apart from the fact that people live together in one place, it is difficult to stress anything else which would determine the consensual nature of the relationship. Particular partners may have various financial issues, divide household chores differently or spend free time in many different ways. There are no standard arrangements in this respect. Many people shack up with each other as at first, they want to try to live together before they decide to get married. Sometimes the final decision is postponed and never happens. Such a lifestyle is now very popular with young people and we cannot expect to witness any opposite trend.

To finish with, let’s focus on the difference between cohabitation and common-law marriage (concubinage). The former requires sharing one flat/house, while the latter may do without it. In colloquial speech, we often use these terms interchangeably. It is not a mistake but we need to know that Polish legislation differentiates between consensual unions and other forms of relationship.