Legal Question in Family Law in Virginia

Sure, I don't know why not as there is nothing in Virginia

law as far as I am aware which requires spouses to provide

health insurance for one another (absent a valid court order

requiring the provision of such coverage).

Yes, the spouse can, but it may turn out to be a bad idea for the spiteful spouse. The spouse who cancels the medical insurance is liable for emergency medical care for the other spouse and, depending, on the circumstances, may be liable for other medical expenses as well. But there is no legal requirement to provide medical insurance generally.