His Warrior's Heart. The Brethren, #1

Mango Ururoa has been an agent for the Kawana family since leaving the Temple of The Brethren as a young man. He does what has to be done to keep them safe, following orders without question. It's a good life, and he lives it with honor, never wanting or expecting more. After fifty years of life, Hashani, cat-shifter, Shonto Galon is sick and tired of being alone. Especially after watching his newly-mated brother live in mated bliss for the past six months.
The head of security for his clan is ready for a woman of his own and all the domesticity involved. While serving a mission, Mango gets caught between a rock and a hard place, and his actions lead him into serving a self-imposed debt of honor to Fael and Bonachi, friends of the Kawana family. While delivering members of Bonachi's crew to a fellow clan's ship, Mango meets Galon and the two realize immediately they're mates.
Surprise would be a mild term for what they experience. Mango had no intentions of ever taking a mate and Galon can't understand why the Gods would pair him with another male. It's not like he's ever been attracted to one before. Life can be crazy, but sometimes you just have to go with the flow and hope for the best. And maybe, just maybe, the Gods knew what they were doing when they matched up two warriors who didn't believe love would ever be written in their stars.