Divorce from Agent
Unless a power of attorney states otherwise, a spouse's authority to act as agent is automatically revoked at the time either spouse files for divorce.  An alternate agent, if any, will be eligible to serve at the time either spouse files for divorce.  Without an alternate agent, the power of attorney will become ineffective upon the filing of divorce, because there isn't an eligible agent named by the document.

Although the agent/ex-spouse's authority is automatically terminated, the principal may still be responsible for giving notice of the revocation to anyone who may rely the ex-spouse's authority to act as agent under the Power of Attorney, such as a bank that maintains a copy for its records.

See: Agent, Role and Duties; Agent, Eligibility; Powers, Scope