I Turned Out to Be the Mother of the Dragon Duke's Twins

The story

Five years ago, Allison was drugged and slept with Duke Jasper, getting pregnant. Her stepmother lied the twins died, abandoning them—but Jasper saved them. Four years later, the kids find Allison. She and Jasper marry by contract. When Marian sells Allison to a pervert, Jasper saves her. She sees his dragon mark—a bloodline secret unfolds.