Dearly Departed by Amelia Wilde

Jacob Chambers expected to be dead.
Not literally, but dead to the world.
Now he’s marooned on a tropical island with his brand-new wife with no way to get home.
Catherine Bettencourt has no choice.
She’s stuck on an island with her brand-new husband, who is broken beyond repair.
They’re both being hunted for revenge.
There’s nobody to save them.
They’ll have to save themselves, or die trying.