New Mexico does not recognize common law marriage, even if you and your partner have lived together for years and for all intents and purposes act as a married couple in New Mexico.
However, approximately sixteen states still recognize common law marriage for couples who have lived together for a significant period of time and hold themselves out to the world as a married couple. Some states are phasing out common law marriage and have enacted rules that only recognize such marriages if they occurred before a specific date.
If you moved to New Mexico from a state that recognizes common law marriage, and you are deemed to have been married under the laws of that state, New Mexico courts may recognize your marriage as a valid one. This happens because under our federal Constitution, each state gives full faith and credit to the laws of their sister states.
However, you would have to prove that you were legally married in the other state before you could have this recognition in New Mexico. This could be an expensive and difficult exercise in the court system. On the other hand, there are many considerations, particularly financial issues, that dictate this path. You should discuss the pros and cons of this kind of case with an experienced family law attorney and probably your accountant before you go down that road.
There are numerous financial issues that should be considered. One reason to consider pursuing this kind of case would be at the end of the relationship if you need and would qualify for spousal support. Spousal support is only available to couples who have been married. Another scenario where it makes sense is when one partner dies without a will and the other would be disinherited unless they were deemed to be a legal spouse. Likewise, there may be estate tax considerations upon the death of a partner. Finally, in case of a legal marriage, the division of property and debt will be governed in most cases by community property principles.
In short, common law marriage is generally not recognized. However, under full faith and credit provisions of the U.S. Constitution, it must be recognized under certain circumstances. The burden is on the couple or party seeking recognition of the marriage and this can be a difficult task.