Does a POA remain valid after divorce?

Some states now automatically revoke it but you will need to check for certain or just reassign someone else and that will override the existing PoA.

It's different in different states. Apparently during the divorce process it can remain valid until the divorce is final. There seem to be variations depending on where you live.
I always thought it would remain valid until it was changed or revoked but to be absolutely sure I would check with an attorney in your state. You don't want to guess at that!

Yes, if you are the POA and do not want to be, see a lawyer about revoking it. If you have assigned someone its just a matter of revoking theirs and assigning someone else, if you want to. When a POA is done it says "this POA revokes all others".

A POA remains valid until the person who designated the POA changes it to someone else or the POA resigns the role and a new one must be chosen