Don't take any of this back story as set in stone. Or even as back story for that matter! Think of it more as a character study of the pair, and an outline of what might
happen between them.Royal Marriage
The man in the picture is her husband, her uncle, and the present King.
Her father was the previous King. He was something of a diplomat, but also weak and much too quick to forgive. He pulled money from the army to fund construction of roads and bridges and palaces. And while these projects mostly improved the economic state of the Kingdom, they did little to improve its defense while making it more attractive to bandits, raiders, and invaders. The King's younger, smarter, more able brother objected strongly to this weakening of the Kingdom, and was banished when he tried to do something about it.
Growing up, the girl worshipped her favorite Uncle - the strong, vigorous, personable man was a heartthrob, and had many admirers among the ladies at court. Even his brother's wife and his own niece had disturbing feelings related to his breath of shoulder and his striking presence. The girl was too young, but the queen succumbed to his rough charm.
When the girl was 16 her Uncle, who was banished at the time, had her abducted and brought to him. His plan was to marry her, the eldest of the royal scion, to secure himself a claim to his brother's throne. While not really condoned by polite society, such marriages are legal in this Kingdom. By now she was flowering into a beauty that eclipsed all others at court, and was a veteran at outmaneuvering suitors that threatened her Royal Chastity. He had her brought to him, and he was just as she remembered, charming, witty, urbane, magnificent. They talked of the Capital and of Court, exchanging anecdotes and discussing events. He was courting her, and courting her well.
But as the evening waned, he informed her that they would be wed on the morn. She objected. He was her uncle! He was old enough to be her father! A lady liked to be asked, rather than informed! He didn't want her, but only wanted her lineage, her station! They didn't have her father's blessing! She had no time to prepare! Her objections were rebutted, one by one, and her protests grew more disparate and less forceful, but they continued. The debate raged for most of an hour, a time where she learned that the thin-blooded nobles at court did not know how to properly hold a girl, and that none of her prior suitors knew anything about how to kiss! Not to really kiss! To kiss urgently, forcefully, with no slight pause coming in to check for permission. To exude passion and to provoke it. She was quite breathless, between recovering from those kisses, and uttering her protests to his intent.
Finally, he sighed. "It's obvious I could convince you." He told her as she stood stiffly but securely in his arms. She opened her lips to reply, but he spoke over her intended protest "With time." He stared her deep in the eyes. "But events are in motion. I am on a timeline. And I don't have time for your girlish games. We will be married in the morning." If he'd asked her at that moment, instead of issuing his brusque command, she might well have agreed, but begging wasn't in his nature.
She protested, perhaps more to his approach than to his intent, and then he backhanded her hard enough to knock her across the room and off her feet. And then he raped her. A large man, he was very strong and was at heart a warrior and a man of direct action. He tore off her clothes and he took her. He took her body, and he stole her virginity. Her preciously hoarded royal virginity! He took her by conquest, with no thought of gentleness and no concern for her desires or her fears. And when he was done, he carried her to his bed.
He slept soundly, with no guilt or doubt haunting his dreams. She barely slept at all, but his mighty arm lay across her flat belly, pinning her to the linen sheets. When he awoke, he took her again. And then he wed his niece. The ceremony was more elaborate and much more formal than she expected, and she was shocked to see some of the faces among the witnesses. Where so many disloyal to her father? Her body ached, her thighs quivered from abuse and exhaustion. And when asked her will, she stared into his eagle gaze and she agreed to be his wife. After the service, he announced to the witnesses that he was off to consummate his marriage. Amazingly, he did just that - robustly and well - though they had vigorously coupled that very morn, prior to the wedding. Afterwards, she was asked to proclaim to the witnesses that she was his wife, and that their marriage was sealed, without coercion, and legally consummated. It all happened so fast, she wanted to protest but it was much too late. And so she made her bridal proclamation. Forever more she could never claim maidenhood.
While she loathes the man that raped her and murdered her parents, her ripe young body has become quite accustomed to his energetic and frequent attentions. In fact, she'll often provoke him just so he'll knock her around a bit and take her - they have a very active sexual relationship, the new King and his young bride. But just because the sex is great doesn't mean that she's loyal or that she loves him. Well, she may love him at some level and she does greatly respect him. Her emotions and desires confound her motives - which are to punish him for his crimes and remove him from power. She's planned treason, planned his murder and the coronation of her younger brother - a mere toddler.
But then the Kingdom was threatened by some horror: An conquest by a distant Empire, or perhaps a monstrous invasion. This was precisely what her husband had expected and planned for, maintaining that the Kingdom was weak and ripe and that it had to prepare and if his brother wouldn't do it, he would. And, it seems, he was right. So she has laid off her plans to usurp the usurper, and she has become his reluctant ally and less reluctant consort while they war against this alien threat.