"To prove constructive abandonment, the spouse attempting to obtain the divorce must also show that he or she made repeated requests for relations during that year, that the other spouse refused those requests and that the other spouse was physically and mentally capable of having sexual relations."
It seems almost impossible to prove, doesn't it? Unless you keep some kind of record... ??
I also found this: http://www.nycourts.gov/ip/matrimonial-matters/summaries/mc-wc.shtml