Attention grabbing opening line "He's never forgiven me for - It was when I put my portrait of his genitals in my exhibition." If the auditors aren't paying attention after that line, check them for a pulse. The monologue goes onto detail Wynne's back and forth tete-a-tete. Each line she recreates for us, enacting both sides of the interaction, is a tactic by herself against him to justify her actions and maintain the upper hand. The last line she reports, his triumphant victory over her, as he justifies his infidelity based on her cruelty. So we go from a feeling from Wynne of slight "duping delight" and dominance to crushed, saddened, a little depressed. Deflated. Ergo, as an actress you get a few tactics to play, a funny banter to re-enact (chance to play a guy's voice and be silly as you enact his side of the convo), and an emotional journey. Not bad and it can be done in under 2 minutes.
Preview the monologue on google books here. The monologue starts on page 10 of the play "Dinner" with the line "He's never forgiven me for" and ends with the line "He was triumphant" on the same page. Get the play here.