In 1979, the Illinois Supreme Court, in a case entitled Hewitt decided that based on the prohibition in Illinois Statutes against common-law marriages, unmarried people who lived together could not bring claims against one another to enforce property rights if the rights asserted are based on a marriage-like relationship between the parties.
Very recently, August 18, 2016, the Illinois Supreme Court decided a similar case entitled Blumenthal v. Brewer. Two women lived together. They were not married to each other. They had a long term domestic relationship. They had raised children together.
Eileen Brewer, a Judge, owned the family home. Jane Blumenthal, a doctor, said in court that she was entitled to a piece of the house because of their relationship. The Trial Court using the Hewitt case said that Dr. Blumenthal was not entitled to any portion of the house. The Illinois Appellate Court for the First District reversed that and said that she was. The Illinois Supreme Court reversed the Appellate Court, affirmed the Trial Court, and held that Hewitt was still good law. Common law marriage is still prohibited in Illinois by statute. This couple was not married. Therefore, Dr. Blumenthal can have no property rights against the property of Judge Brewer nor the reverse.
The only way unmarried cohabitants can have property rights against each other is for them to have a valid contract permitting it. However, as the Court said in Hewitt, the contract cannot be based on having sexual relations. There has to be some other legal form of consideration.
Couples planning on living together, regardless of gender, in order to protect property rights, should seriously consider getting married or entering into a civil union. There may be very valid reasons for not being married. However, if the couple wishes to assert rights to the property of the other, they should consult with an attorney who can help them structure their property titles and a contract between them to effectuate the desired result.