A story in the Tennessean by Janell Ross goes through the tangles cohabitors get themselves into when they split up. She tells the sad tale of a doctor who sued his former girlfriend for $46,000 to get back what he put into the house they bought together. The judge said that since they were not married, and had not made any legal agreements about who got what in the event of a breakup, Dr. Out-of-Luck had made a gift of the house to his girlfriend in the course of the relationship. The doctor's haul from the legal suit: $0.
Serves him right, I say.
If people want to have a marriage-like relationship but won't or can't marry, they should make a legal contract, or suck it up. If they think marriage is "just a piece of paper," then so is a mortgage -- the kind you have to pay to the bank, no matter what happens to your feelings.
If you want the legal, financial, and social benefits of marriage, then get married.