The Virtues of Kings. The Cursed Princes, #4

Prince Gabriel is a fallen hero. Once the darling of Peony Realm, a surgeon-general and an accomplished dancer, he spends his days hiding from the court, drinking too much wine and avoiding the scorn of his people. Fed up, the King gives Gabriel an ultimatum: return to the army or marry. The King doesn't understand. Gabriel can't do either. He is plagued by nightmares of killing a man, and he can't share intimacies with another person any more than he can pick up a sword or a scalpel.
But the realm needs allies, and Princess Elvire is an excellent match, despite being cold, unpleasant and up to something that might amount to treason. The more Gabriel learns about the Princess, the more intrigued he is. Still, it doesn't change the fact that he can't let her see the wreck of a man he's become. To be a Peony prince, after all, is to be valorous. As the threat of war looms closer and the need for allies grows desperate, Gabriel and Elvire must find a way to share their secrets and redefine what it means to be heroes.
The Virtues of Kings is a queer MF arranged marriage romance. It is the fourth book in the Cursed Princes, a series of quick romantasy reads with angsty happy endings. Each title is a standalone romance but the books are best read in order to understand the series arc.