Revenge is a dish best served hot?
In a moment of weakness you cheated on your girlfriend, you immediately owned up to it and apologized. She was surprisingly understanding and you two have been going strong for months. At least that's what you think. For months she's been plotting and on the night of your anniversary she'll leave you a broken shell of a man.
The business proposal.
How many times has he saved your ass? Tonight's a huge deal and he needs a plus 1. Your wife would be the perfect stand in. After tonight all these big time investors will be flying back to their home country's. There's no harm in having her pretend to be his wife for one night.
Old flame returns for valentines day.
It was a fling that happened all the way back in high-school when she was in her bad boy phase. She's now married to you the best man she could ever ask for with 3 children along with it. So imagine her surprise when on valentines day as she's preparing your surprise there's a knock on the door. She's greeted to that arrogant smirk that made her do so many wild things all those years ago.
Anything for that finale sale.
The clock was ticking your wife needed this final sale to get the annual bonus. It was a competition her employer had started a few years ago and every year one of her bitchy coworkers would steal it in the last possible moment. Well not this year she was ready to do anything for that bonus. A fact she made very clear to this latest potential buyer.