Tenants in Common
/When two or more people unmarried to each other co-own real estate, they own either as tenants in common, or joint tenants. When married, they own as community property.
When people own as tenants in common, they have some flexibility in ownership. Tenants in common can own in unequal percentages. This can be important where one person invests more than the other in the property. Also, when one tenant in common dies, their ownership interest goes according to their will (or the law of intestate succession). This works well when the co-owners are not also in a life relationship.
For an unmarried couple, ownership as joint tenants may make sense. Joint tenants own in equal shares. When one dies, the ownership automatically passes to the surviving owner.
For more, here is a good blog post on co-ownership of real property by single people (on FSBOLawyers.org).