Let Sleeping Foxes Lie by Sam Burns

Max has settled nicely into life in Welling. He’s got the best boyfriend ever born and a life he never imagined he could have. He’s also written his new screenplay, and the hottest director in Hollywood has snapped it up enthusiastically.
So what’s the problem? She’s asked for a two-week long retreat, hosted by him, in his home, with the actors who’ve been cast in the movie. Between the personal disagreements, the weird flirtations, the easily bruised egos, and the fact that one of them invited his family along, the first week has already been hellish.
All he wanted to do was find the right time to propose to his boyfriend.
Things take a turn for the worse when one of the actors is murdered, and the best suspects are Max, his family, and his houseguests. The sheriff is no help at all, so Max needs to discover who the killer is before someone ends up behind bars.