In Plautus' Menaechmi, the wife is simply called Matrona, which is the Latin word for wife. As with most characters in Plautine comedy, the wife is a stock character, i.e., she is a stereotype. In this case, the Matrona is stereotyped as a nagging wife. She stands in the way of Menaechmus of Epidamnus having any fun.
The most detailed characterization of the Matrona occurs when Menaechmus of Epidamnus first appears on stage. He emerges from the house complaining about his wife's behavior, in particular that she is constantly asking him a number of questions:
For as often as I wish to go out of the house, you are detaining me, calling me back, asking me questions; whither I am going, what matter I am about, what business I am transacting, what I am wanting, what I am bringing, what I have been doing out of doors? (Henry Thomas Riley translation)
Of course, who can blame Menaechmus' wife for being suspicious? After all, she knows he is paying regular visits to the prostitute Erotium and giving away her clothing to this prostitute. Still, Matrona's role in the play is to prevent Menaechmus from having fun. We should note also that at the end of the play, Menaechmus of Epidamnus decides to auction off his property, including his wife.