My husband is a disfellowshipped Jehovah's Witness and he has filed for a divorce.
What is the Jehovah's Witness belief about divorce and the responsibility of the husband to a non JW wife?
Jehovah's Witnesses believe adultery is the only appropriate reason for divorce.
You stated you had not committed adultrey (before @AffableGeek removed that). Thus, Jehovah's Witnesses would say the divorce is unjustified. This can be grounds disciplinary actions (though it appears your husband has already undergone that).
This is true regardless of the spouse's faith.
If the spouse actively prevents the other from following God, or is abusive, divorce is somewhat acceptable. But in this case, the person may not remarry while the spouse is alive, or else they are guilty of adultery. It is more of a separation than a divorce.