I do not know what the jurisdictional requirements are in DC, and perhaps five months is sufficient for him to file for divorce, although it seems a little short. In order to prevent the case from being heard in DC, you should file for divorce first in New York on the grounds of abandonment. New York would have jurisdiction because you lived here for over a year and were married in New York. Once the case is commenced here in New York, he will not be able to file in DC, and will have to deal with New York law.
Do not waste time. File first. Call me I can help.
If you are living in the New York City metropolitan area, please call me at 212-370-1660 to discuss mediating your divorce. It will save you time and money and lots of aggravation.
Leonard M. Weiner, Esq./Divorce Solution