Actors are disreputable.
Theater, or any occupation where you appeared on stage, was long held to be a disreputable profession in modern Europe -- under some laws, an actress could not sue for slander because her occupation meant she could not have a reputation to protect. This led to a self-fulfilling situation, in which many women avoided the stage to protect themselves. The plots of many plays did not help the matter. (Also, actresses painted.) Unsurprisingly, it was reflected in literature, though a Forgotten Trope today. It's mostly a female trope, since A Man Is Not a Virgin. In early works, it would mostly be used as a shorthand to indicate that an actress was The Vamp. As the stigma of acting decreased, it became a way to indicate the desperation of a poor family, that a daughter or wife would go on stage, or an obstacle to love, where the young man must get his parents to revoke the Parental Marriage Veto inspired by her occupation.