The Unhoneymooners

Christina Lauren's The Unhoneymooners, published in 2019, is built on a pair of identical twins with opposite luck. Olive has bad luck with her career, with love and with most other things, while her sister Ami has all the luck going: her meeting with her fiance came straight out of a romantic comedy, and internet contests have covered the cost of the whole wedding. The wedding also means that Olive has to spend the day in the company of Ethan, who is Ami's best man and Olive's least favourite person.

At the reception, the shellfish makes everybody else at the wedding ill, and Olive and Ethan turn out to be the only two guests who are unaffected. That leaves a prepaid honeymoon in Hawaii going unused, and the two of them end up taking the trip together, which is not the holiday either of them would have chosen.

Christina Lauren is the combined pen name of Christina Hobbs and Lauren Billings, who met in 2009 while writing fan fiction online and became co-authors in 2010. The Unhoneymooners was published in 2019 and is one of the novels they have written together under that name.