Psychologist SHIRLEY GLASS talks about infidelity. GLASS is a marriage and family therapist who's been cited for her expertise on sexual and relationship problems in the national media. She is working on a book about the trauma of infidelity. GLASS answers questions about relationships on the internet, at www.electra.com. She's also been a guest on NPR's "This American Life," hosted by her son, Ira Glass.12:58:30 NEXT SHOW PROMO (:29) PROMO COPY On the next Fresh Air . . . lying and cheating. First, Marty Moss-Coane talks about how the courts handle perjury with legal correspondent JEFFREY ROSEN. Later, Marty talks about extramarital affairs with psychologist SHIRLEY GLASS, who, by the way, is the mother of Ira Glass, host of NPR's "This American Life." That's all coming up on the next Fresh Air.