The Sea Prince. The Coral Throne, #1

Tarjiaan was the sixth prince of war-tossed Meradon, destined to be a simple ship captain like his father. Then tragedy leaves him the only heir, separates him from the man he loves, and forces him into an arranged marriage with the granddaughter of his people's greatest enemy. He never expected to fall in love with his bride, or to be reunited with his first love. And when the king is murdered and Tarjiaan captured, the only people who are left to save him are his lover and his wife. War is all they've ever known.
To save the Sea Prince, they'll have to choose love.