Is a durable health medical POA legal if theparties are divorced and were legally separated at time it was executed?

The health power of attorney may still be legal and enforceable. A person has a right to make *anyone* his attorney in fact for medical decisions or other reasons--a spouse, a child, a sibling, a friend, a lawyer, or an ex-spouse. Assuming the POA was properly made while competent, it will survive the maker's incompetence--that's the whole point of it, after all.

Where there could be an issue is if you were identified in the POA not just by name, but as, for example, "my wife" or "my wife, Jane Doe." In the former case--just identified as "my wife," a court could find (if the POA is challenged) that the intention was to only make you the attorney in fact because you were his wife, so that now that you are not, it is no longer valid. In the latter case, "my wife, Jane Doe," there is at least a question as to your ex-husband's intentions--did he want you to remain his attorney in fact after you were no longer married? If so, why did he identify you as "my wife, Jane Doe." Other evidence could be introduced to show that he was not worried about marital status--e.g. the fact that you were legally separated at the time--but it would possible to at least raise the issue.

If the POA only identified you by name, then it would seem likely that it would survive any challenges based on marital status, since marital status did not seem to factor into the designation.

In sum: marital status does not automatically affect a POA. However, depending on the facts, when the POA was executed, the language used, etc., it may sometimes be possible to challenge it on the grounds that the maker's intention was to only grant the power while still legally married.