I was absolutely, positively certain that was what was going on Carol Berg's Transformation. You could have cut the sexual tension between the two main characters with a spork! It's slavefic, which can be very, very icky a lot of the time, but Berg makes it not be icky. Basically, the slave (Seyonne) is sitting quietly judging the everloving fuck out of his master (Aleksander) every time he acts like an asshole (which is all the time, pretty much) and it drives Aleksander crazy, learning to see himself from a slave's perspective, and eventually he starts showing compassion--a teeny bit, but still. Then stuff happens involving a secret war with demons and a curse. Aleksander and Seyonne have to run for their lives. Seyonne finds out the woman he loved and his best friend left him for the slavers when they could have rescued him. Then, towards the end of the book is this little gem:
I had wondered about it myself. Aleksander could not prevent me [removing the slave collar], and I wasn't sure he would try. But on that night, as the first stars popped out of the deep turquoise of the sky, I finally understood my hesitation. Something extraordinary had come about between Aleksander and me. Something beyond oaths, beyond duty, beyond necessity and desperation. If the Prince unlocked my chains, I would not walk away. But until Aleksander believed it, I had no name for him but master, and no name for myself but slave. And inside I am yelling YES IT IS CALLED TRUE LOVE, GET ON WITH IT PLEASE. To me that reads pretty clearly that Seyonne at least has realized that what he feels is deeper than just genuine respect and friendship. I was deliciously anticipating the moment when Aleksander finally got a clue, but it just never came (he does set Seyonne free though). They both end up with women; Seyonne finds out his girlfriend was tricked by his best friend, who conveniently dies at the end, and, well, Aleksander isn't married yet, but it's implied that his future marriage to his betrothed won't just be a marriage of convenience.
I am not entirely sure if Berg is really that clueless, or trolling the everloving fuck out of m/m readers. (If so then A for effort?)