It is not uncommon for couples who are committed and have been living together for some time to buy property together.
This can present problems both while the couple stays together (or when one partner dies), and if the couple ever splits up.
Some of the problems can be solved by holding the home or other real estate not as tenants in common, but with right of survivorship. Deeds (in Oregon) which say “joint with right of survivorship” are not technically proper and can cause problems. Deeds which refer to the couple as husband and wife, or as spouses (including same sex spouses), or which say “as tenants by the entirety” create significant difficulties if the co-owners are not actually married. Even if the couple later does get married, this will not correct the problems caused by taking title as spouses or as tenants by the entirety before marriage.
Other problems can occur if one partner eventually needs Medicaid.
Of course if the intent is not for the survivor to have the property, this can also create problems. In such a case, one would not want to create a survivorship interest.
Sometimes people try to solve the problem of not wanting to hold the property with right of survival by giving the non-owner (or the other part owner) a life estate, so that they can remain in the property for the rest of their lives. This also can create problems for Medicaid, or can even result in the property being lost to Medicaid estate recovery instead of passing to the intended remainder beneficiary.
Turning to a somewhat different issue, if the couple ever splits up, the ownership of real estate can cause significant problems. Some of these problems can be solved by careful documentation of intent, or even by the creation of trusts or the like. Some of the problems can be more difficult to resolve.
In general, however, the results of the dissolution of a marriage-like relationship between people who are not married can be much more difficult to predict, and much more uncertain, than the results of a divorce are.
Adding an unmarried partner to real estate can create significant difficulties, and can end up costing a great deal that one might not expect. Careful forethought, and consultation before one does anything, with a lawyer who understands both elder law and family law, can be very helpful.