As the social stigma attached to non-marital cohabitation and childbearing has faded, many couples have come to believe that the commitments and burdens of marriage outweigh its advantages. Yet, despite this more informal type of living arrangement, there is also a need to predetermine how property will be distributed upon dissolution of the relationship. Like prenuptial agreements, cohabitation agreements are governed by contract law and specify each party’s rights in the event of separation.

Historically, courts have refused to enforce contracts between nonmarital partners if they involved an illicit relationship. Any such agreement was viewed as a contract for prostitution, and therefore, illegal or contrary to public policy. Today, the majority of courts which have considered this issue have recognized the prevalence of nonmarital relationships in modern society, and the social acceptance of them.

Example: Jerry (a dentist) held out a woman as his wife for 15 years. In that time they had three children. When she sought a divorce, he confronted her with information that they had never been legally married. The Illinois Supreme Court held that any contract the couple might have made concerning their property or support obligation would be unenforceable as an “agreement in consideration of future illicit cohabitation.” Further, it was the legislature not the court’s job to change the law. See, e.g., Hewitt v. Hewitt, 77 Ill.2d 49, 394 N.E.2d 1204 (1979).

The trend toward “conferring the benefits of marriage upon persons who clearly were not married, and who had no intention of being married” began with the leading case of Marvin v. Marvin, 557 P.2d 106 (Cal. 1976).

Example: Actor Lee Marvin, while still married to Betty, had begun an affair with Michelle Triola. They lived together for nearly seven years, during which time Lee divorced Betty. Michelle changed her name to Marvin and agreed to “devote her full time to [Lee] . . . as a companion, homemaker, housekeeper and cook” in exchange for Lee’s promise of lifetime support (via an oral agreement). When they separated Michelle sued for one-half of the property acquired by Lee while they were together, and for support. The court stated that “a contract between nonmarital partners is unenforceable only to the extent that it explicitly rests upon the immoral and illicit consideration of meretricious sexual services.” However, where other services are part of the contract, and they are supported by independent consideration, that part of the contract will be enforced if it is severable from that part of the contract involving sexual services. See Marvin v. Marvin, 134 Cal. Rptr. 815; 557 P.2d 106 (Cal. 1976).

Accordingly, various remedies may be used to recover if the immoral or illegal aspects of the relationship can be separated from the lawful ones.

• Express contract: If nonmarital partners make a contract it should be enforced except to the extent that the contract is explicitly founded on the consideration of meretricious sexual services.
  
• Implied contract: Courts may imply a contract, agreement of partnership, or joint venture between the parties based upon their conduct.
  
• Quantum meruit: Courts may employ the doctrine of quantum meruit (recovery for the reasonable value of household services rendered, less the reasonable value of support received), if one person can show that the services were rendered with the expectation of monetary reward.
  
• Constructive trust: When a court determines that one party holds property that rightfully belongs to another, a constructive trust may be created. This forces the person with title to convey the property to the one who should have title. It is usually a remedy for fraud, duress, mistake or undue influence.
  
• Resulting trust: This is a doctrine of construction based on presumed or implied intent. It attempts to do with property what it is presumed the transferor would have wanted, had he anticipated the situation.

Subsequently, allowance for legally enforceable property rights arising from cohabitation has met with broad acceptance nationally. Today, approximately 30 states recognize express agreements between unmarried cohabitants.

Example: Mary and Jonathon agree to live together and hold themselves out as married. Mary gives up her job, assumes Jonathon’s surname and works in his business. Mary gives birth to two children and contributes childcare and homemaking services. Several years later Mary starts a business with Jonathon’s sister-in-law. Subsequently, Mary and Jonathon split up. Mary sues Jonathon, alleging that they had a contract to share equally the property accumulated during their relationship. The court held that state law did not preclude an unmarried cohabitant from asserting contract and property claims against the other party in cohabitation. In addition, public policy does not preclude such a claim as long as the claim exists independently of the sexual relationship and is supported by separate consideration. As such, Mary may recover on an express or implied contract if she can prove the agreement existed. See, e.g., Watts v. Watts, 405 N.W.2d 303 (Wis. 1987).

In contrast, only three states—Georgia, Illinois and Louisiana—have refused to recognize property rights arising from or in connection with alleged contracts between unmarried cohabitants. See, e.g., Doe v. Buckland, 808 A.2d 1090, 1094 n. 4 (R.I. 2002); Hewitt v. Hewitt, 394 N.E.2d 1204 (Ill. 1979).

Although cohabitation may be an effective substitute for marriage for many couples, many couples decide to formalize their relationship. The next chapter will discuss what steps a couple must satisfy to achieve a valid marriage.