Although there is no definition of cohabitation in Polish law and this type of relationship has not been formally sanctioned, the legislator mentions „persons in common cohabitation” several times. According to increasingly emerging case law, the concept of persons in common cohabitation also refers to persons of the same sex who are connected by spiritual, physical and economic ties. We also speak of cohabitation when the persons in it, are married in parallel.
No formal basis is required for the acceptance of cohabitation, the only constitutive element is the community of life. The provisions of the marital property regimes will also not apply to cohabitation. Thus, no statutory community of property is formed between persons in an informal relationship - each partner retains his or her separate property, and consequently, the provisions on the division of property between spouses will not apply to the division of cohabitants' property. Due to the lack of unambiguous regulations in this area, the settlement of concubine property is one of the most problematic issues.
Experience shows that cohabitants do not regulate financial issues through the available institutions of civil law (simply put, through contracts), relying instead on verbal agreements and assurances. Most difficult is the settlement of expenditures made on an item belonging to one of the partners. In the case of the division of an object that the cohabitants acquired jointly, the matter is much simpler; the provisions on the abolition of joint ownership will then apply.
Depending on the specific facts, the basis for property settlements between cohabitants will be the provisions on joint ownership, civil partnership, unjust enrichment, commission, provision of services or labor. At the same time, as indicated in the doctrine, the application of the provisions on unjust enrichment is possible only as a last resort, when there is no other legal basis for the settlement. It is worth noting, however, that there are situations in which the fulfillment of a benefit to a concubine will do justice to the principles of social intercourse and thus will not be subject to settlement.
Notwithstanding the above, it should be mentioned that the acquisition of an item with a cohabitant, while married, will result in the item being jointly owned by both the cohabitant and the spouses (if, of course, the spouses' statutory community of property has not, through the establishment of a separation, been excluded).
