Here's the thing.
About 95% of employer-sponsored plans in the US are covered under Section 125 of the IRS code. If your portion of the premium is taken pre-tax, or if taking it pre-tax is an option, then your plan is a 125 plan.
Under 125 plans, once you make your elections during your initial hire, or your annual open enrollment period, you are locked into those elections for the entire plan year unless you have a qualifying event. Then the change can only be made as of the date of the qualifying event. You have a window, usually 30 days (never shorter, occasionally longer) after the qualifying event to make your elections, which are retroactive to the qualifying event date.
But the kicker is that you need independent verification of the qualifying event supporting it. The court order would bypass that requirement.
It's not entirely clear to me how you enrolled in your wife's plan and how long after you attempted to drop your employer's coverage. Was it your wife's open enrollment period? Her first date of hire? How long after that did you attempt to drop your own coverage?