a student expelled from george mason university for violating its sexual misconduct policy is suing in federal court to clear his name .
the man is arguing an encounter with a girlfriend was sadomasochistic role playing , not sexual assault .
the sexual misconduct allegations stem from an october 2013 encounter with the couple in the male student 's dorm room on the fairfax campus .
at one point , according to the lawsuit , she pushed him away but did n't invoke her safe word .
later that night , the two engaged in a second sex act , in which the male student asked her if she was interested , and she replied , ` i do n't know '
the lawsuit claims the woman only filed a complaint months later , after the couple broke up and she had found out the man was cheating on her .