The most fascinating tension Masters of Sex explores isn’t sexual. It’s the one that exists between the public and private lives of patients treated by sex researchers William Masters (Michael Sheen) and Virginia Johnson (Lizzy Caplan). As season 3 begins, Bill and Virginia are starting to feel that tension themselves. It’s 1965, and the duo are preparing to release their first book, Human Sexual Response, which would make them famous far beyond the medical community. Soon they’ll be the public faces for a very private subject, and they’re both feeling a little exposed. Virginia experiences scrutiny from critics who question her medical credentials, while her ex-husband (Mather Zickel) threatens to take custody of their children, worried that they will be scandalized by her reputation. And Bill’s strained marriage to Libby (Caitlin FitzGerald) now exists in name only, for the kids’ sake. In the two episodes made available for review, the steamy morality drama has become a thoughtful rumination on the sacrifices that parents (especially mothers) make for their families.