Royal Mate by Grace Goodwin

How can I stand by while she chooses another, when my heart, my soul, and everything I am screams that she was born to be mine?

She appeared in Alpha Station like a lightning strike—unexpected, breathtaking, and utterly unstoppable. A human woman, demanding answers, demanding to go back to Earth. But the moment Paige stepped into my world, I knew the truth, she belonged to me.
As a male of honor, I tried to honor her wishes and send her home. The Coalition Fleet refused to allow her return to Earth, and then revealed the truth about her past.
She’s not human. She’s Insurian royalty, stolen as a child and believed dead for twenty-five years, and raised on Earth. Her sudden return has shaken the planet, and the throne she never knew she inherited comes with a dangerous legacy. The same traitors who murdered her parents are still here, watching, waiting for their chance to strike.

The long-lost princess is betrothed to a prince, bound by a contract written before she was born.
She’s not mine to claim, but I can’t let her go.