The New Mexico Durable Power of Attorney Form is used when the Principal wishes to ensure that their Agent will continue to serve as their Agent, even if the Principal is declared incapable of making their own decisions. This sort of agreement is usually Springing, IE will only go into effect once the Principal has been declared incapacitated, but this is not always the case.
In New Mexico, a Durable Power of Attorney is extremely difficult to break. Unless the Principal voluntarily revokes it or the Agent is unable to fulfill their role, it is very rare for it to be invalidated. The agreement will still be valid even if the Principal and Agent are spouses and get a divorce, although there is a slight chance that a judge will declare it invalid in that case.