I was imprisoned by the Unicorn

I'm a wildlife researcher. I brushed a mysterious white horse's mane—and accidentally proposed to an ancient Alpha Unicorn. He turned into a gorgeous man, chained me in his mountain cave, and swore I was his mate. A forgotten childhood promise made me fall for him. But when I trapped him in a lab, I shattered his trust. Now I'm pregnant with his child, and the only way to keep him may be to set him free.