The Companion by Lloyd A. Meeker


 Shepherd Bucknam hasn’t had a lover in more than a decade and doesn’t need one. As a Daka, he coaches men in the sacred art and mystery of sexual ecstasy all the time, and he loves his work. It’s his calling. In fact, he’s perfectly content—except for the terrors of his recurring nightmare and the ominous blood-red birthmarks on his neck. He’s convinced that together they foretell his early and violent death.When Shepherd’s young protégé is murdered, LAPD Detective Marco Fidanza gets the case. The two men are worlds apart: Marco has fought hard for everything he’s accomplished, in sharp contrast to the apparent ease of Shepherd’s
inherited wealth—but their mutual attraction is too hot for either of them to ignore.

Shepherd swears he’ll help find his protégé’s killer, but Marco warns him to stay out of it. When an influential
politician is implicated, the police investigation grinds to a halt. Shepherd hires his own investigator. Marco calls it dangerous meddling. As their volatile relationship deepens, Shepherd discovers his nightmares might not relate to the future, but to the deadly legacy of a past life—a life he may have to revisit before he can fully live and love in this one.

https://www.goodreads.com/book/show/22575659-the-companion?ac=1
As a warning this book contains discussions of past child abuse in one of the main characters.
The main plot of this book was very interesting but it was the side plots where this book got a little convoluted.  The main plot in this book is Shepard wanting to help in the investigation to find out who murdered his best friend; however one of the side plots deals with the purpose of life and discusses other such existential questions.
While everything was handled in a very clear way, I just did not care for this particular plot twist. The thoughts this book evokes are very interesting and the plot line worked wonderfully to further the growth and development of the main character I just was not a big fan of it.
Overall it is a good,  well written m/m romance novel.