The Unhoneymooners by Christina Lauren

Olive is always unlucky: in her career, in love, in…well, everything. Her identical twin sister Ami, on the other hand, is probably the luckiest person in the world. Her meet-cute with her fiancé is something out of a romantic comedy (gag) and she’s managed to finance her entire wedding by winning a series of Internet contests (double gag). Worst of all, she’s forcing Olive to spend the day with her sworn enemy, Ethan, who just happens to be the best man.