The Pretend Fiancé Fiasco by Pippa Grant

Davis Remington is the last member of a former boy band group who isn't in a relationship or married. He was the one who broke up the band (at least in his mind) lo, those many years ago. Now, he does computer stuff. His friends and family are convinced that he is involved in the government somehow but he denies it. It's sort of a plot point but there are a lot of plot points. 
Sloane Pearce is a nurse but she is also a volunteer in the Shipwreck Museum. There's a lot going on since she is helping with a celebrity wedding the same day that her sort-of-ex shows up in town wanting to drag her back and someone breaks into the museum. The ex is there because Sloane told her grandmother that she was dating Davis. When she tells Davis, he's like, okay, let's get married. Because he's done this fake wedding thing before. Multiple times. 
So, lots and lots going on this book. The treasure aspect (oh yeah, there's buried treasure and Davis and a few other people are racing to figure out where it is) is most of the story rather than Sloane and Davis. Also, for a character who is called "Manbun," the guy on the cover sure has short hair. 

Three stars

Bro Code #6

This book came out May 8, 2025

Follows Snowed in with Mr. Heartbreaker

Borrowed as ebook from Kindle Unlimited

Opinions are my own