Is ths a JW thing or is he just being pig-headed?
Both. It is a "JW Thing" to withdraw from a "weak one", apostate, or non-believer as a way to make them choose between being in the organization and loss of loved ones. It is pig-headed to not cooperate with bringing to an official end to what has become a marriage in name only. If he was not being pig-headed, he would speak to you, seek professionkl counseling, etc., not withdraw his affection and attention.
Laws vary from place to place. You should seek competent local advice; what applies where I live may not be allowed where you are.