Can my wife legally drop me from family health plan even though we are still married? I'm in NJ...she's in PA.

You remain married and would still be covered under a family plan through the spouse's employer (although you don't mention if the divorce is proceeding under NJ laws or under PA laws, which may have different laws). She would have to change a plan from family to single coverage and if there are children covered under her plan, she would not be able to do that. If for some reason she does try and remove you, you could possibly file a complaint for temporary coverage until the divorce (it is called a motion for pendite lite).