This article explores the persistent problem of bisexual invisibility in contemporary film and television and asks why, in the rare moments bisexuality is visible, it is likely to collapse back into dominant stereotypes of bisexuals as unstable, immature and incapable of monogamy. Through a reading of You Me Her, a television series about a polyamorous triadic relationship, this article argues that bisexuality is both made evident and obscured by the dominant temporalities of monogamy. Drawing on work from scholars in critical monogamy studies and queer temporality, it therefore offers ‘mono-temporality’ as a new theoretical resource for explaining bisexual in/visibility on screen.