As for the love debt dispute, the judicial practice adopted the theory of natural debt under the guidance of the spirit of "Passive Intervention and Intermediate Intervention". Both extramarital cohabitation and unmarried cohabitation are the private matters of parties concerned. It is inconvenient for the law to interfere, leaving it an autonomous area for the parties. However, asking for property benefit through cohabitation is a violation of public order and good customs which naturally cannot be realized through judicial power. Still, the request to share reasonable expenses, such as medical expenses and nutrition costs, during the period of pregnancy, is different from asking for property benefit. Based on the theory that a donor, who is at fault, should not benefit from extramarital cohabitation, the donor's claim for the return the donated property should not be upheld.
Extramarital cohabitation violates monogamy and is detrimental to public order and good customs. The necessary intervention of public judicial power is conducive to reflecting the evaluation of society. Husband and wife have equal rights to deal with joint property, and the joint property of both spouses should be protected by law. The fact that the donor donates the joint property to a paramour damages the property rights and interests of the other spouse and the other spouse may claim restitution.
