No lawyer can ever represent both parties in a divorce, even if the case is uncontested because a conflict of interest exists. This ironclad rule applies to any negotiations in which the parties are adversaries, and it includes premarital agreements.
This same code of ethics exists for experts. If one spouse hires an appraiser, his or her spouse must hire a different appraiser. An expert can not provide services to both sides of a divorce case due to a conflict of interest.
A judge may have a conflict of jurisdiction.