Imagine a night out at a nice restaurant. The pair of you all dressed up in your nicest clothes. The sounds of violin music filter through the mingled conversations of other happy couples. A clever joke and a matching laugh. Candlelight dances across the features of her face. A mischievous smile. Wine is poured. The smile gets bigger. You've never seen her look so happy.
A look which immediately leaves her face when she turns away from her date and sees you, seated across the restaurant, with another man.
To pull this one off, you'll need to know in advance where your ex will spend their time on Valentine's Day. This will involve some form of prior intelligence, like knowing what her favorite restaurant is, or how to tail a car without being spotted. After she arrives, you simply arrive a few minutes later with your own date, a guy named Robert, who despite being a casual acquaintance from work, agreed to wear something snug and provocative in exchange for a free meal.