CBG. It isn't an ex-spouse yet. While divorce has been field for it has yet to be granted. I know of no employer or policy (and certainly not VSP) that requires a not-yet-ex spouse to be dropped.
I call shenanigans on the dropping OP outside of the open enrollment and before the divorce. Not to mention that the OP should have been given COBRA notice if he was dropped by notifying the employer that the divorce was final.

