Jilly Cooper 
A Pressing Engagement (Storycuts) 

Frustrated secretary Esther is desperate for a change. She»s been in the same job for years, working for dear Mr Pethrie, and has been waiting patiently for the love of her life, gorgeous professor Julian, to finally divorce his wife. So when the prospect of a fabulous job abroad comes along, Esther leaps at the chance. There»s just one problem — she needs to start immediately. To avoid hurting the feelings of Mr Pethrie, who has been so kind to her all these years, she tells him that she is actually leaving her job in order to get married after a whirlwind romance. Julian is nowhere to be seen, so the job of fake fiancé falls to her trusty childhood friend Nico. But what started out as just one little lie soon spirals out of control…
Part of the Storycuts series, this short story was previously published in the collection Lisa & Co.