Myself and a female co-worker had an alteration with another employee the other day that nearly let to a fist fight. We both filed a complaint against him for making verbal and physical threats. Several female co-workers also filed sexually harassment charges against this man the same day. Now, the female and I that were involved in the near fight are being charged by this guy for "inappropriate sexual behavier at the work place." One the things he claims happen between the female and myself, never happened. And second, how can he have anything to say about it, even if it did? I guess what I'm asking is; If something happens between person A and B the is confirmed welcomed and not offensive to each other, can a person C witnessing hold a harassment suite?

Yes, they can. The law recognizes the concept of "third party harassment".