McLEAN, Va. -- A student expelled from George Mason University for violating its sexual misconduct policy is suing in federal court to clear his name, arguing that an encounter with a girlfriend was sadomasochistic role playing, not sexual assault.

A hearing in the case is scheduled for Friday in Alexandria. The ex-student has sued under a pseudonym to protect his privacy. The university is demanding he identify himself publicly, despite arguments that doing so would expose not only him but the woman who says she was assaulted.

The student says he had been in a longstanding relationship with the woman, and that they frequently engaged in sadomasochistic role playing that involved using a safe word if one or the other wanted to stop.

The lawsuit comes as colleges across the country, and particularly in Virginia, are under increased scrutiny for how they respond to allegations of sexual assault. The University of Virginia implemented changes in its sexual misconduct policy in the aftermath of a now-discredited Rolling Stone article alleging that school officials were indifferent to allegations that a student had been raped at a fraternity party.

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The sexual misconduct allegations at George Mason 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 didn'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 don't know."

According to the lawsuit, the couple remained romantically involved for several months, but they broke up after she found that he had been cheating on her. It was only then that she filed a complaint against him, according to the suit.

In September, a university panel conducted a 10-hour hearing to determine whether the student had violated the university's code of conduct. A three-person panel cleared him of any wrongdoing, according to the suit.

But the woman appealed, and a university administrator, Assistant Dean of Students Brent Ericson, overruled the panel and expelled the student.

The lawsuit says that the appeal was handled improperly. It seeks an order that would strike the violation from his student record, and $3 million in damages. The lawsuit claims that the expulsion was a result of gender bias, and also claims that it violated his right to engage in constitutionally protected sexual activity.

"The only explanation for such a rash, unreasoned, and unsupported decision is Mr. Ericson's desire to help a complaining female when the system had found a respondent male not responsible. If Jane Roe (the pseudonym for the unidentified female student) were not a female complaining of sexual assault, her testimony would not have been credited over John Doe's given the evidence corroborating John Doe's explanation of their BDSM relationship and the material concessions Jane Roe made at the hearing," the student's lawyers wrote in their complaint.

A GMU spokeswoman declined comment on the lawsuit. The university, in court papers, wants to overturn a judge's decision allowing the student to sue anonymously. The university's lawyer writes that the male student should have no fear of embarrassment if the allegations are true, because the public is increasingly accepting of unusual sexual relationships. And he argues the risk of the woman's identity being exposed is minimal compared to the public's right to an open judicial proceeding.

"Even if Ms. Roe is identified simply by the fact that Mr. Doe is identified, there is nothing in the record to suggest Ms. Roe will be subjected to retaliatory harm," Assistant Attorney General David Drummey wrote on behalf of the university.