When John and Chad come to Syracuse University in 1994 to visit John's sister Cheryl McClellan and her roommate Eve Riley, Chad discover a common interest in theoretical mathematics with Cheryl, and the two spend hours together in heavy complex technical discussions; eventually they lead to a closer personal relationship. Chad knew about Cheryl and Eve having been through SRS. He was comfortable with this because, as he said, I have a gay brother who taught me a long time ago that you do what you have to do to be happy.GM24
Chad switches to Syracuse to do his doctorate in 1994 (when Eve gets her masters degree and moves to Brown University for her PhD). When Chad and Cheryl get their PhD's, they move to Maryland, working for a company doing secret mathematical research.
There's no mention in the book The Girl in the Mirror whether they actually are married or not.