How is the drama of Oscar Wao's life shaped and complicated by the contours of Dominican history, both under Rafael Trujillo and in the long, contentious aftermath of his dictatorship?

The simple answer to this question is that because Oscar's family lived through the trauma of Trujillo's dictatorship, he was raised in the shadow of that pain. His grandfather protected his family for as long as he could, but eventually Trujillo touched even his rich and privileged life. His mother, the only one to survive the fallout, has the bad luck of falling in love with the husband of Trujillo's sister. She is beaten nearly to death for it and grows up to become an exhausted and sometimes cruel mother. The drama of Oscar's sister running away, being dragged home, and then being sent to the Dominican Republic plays out—a long and unending theatrical performance.
Throughout the novel, the importance of fuku is expressed by the narrator. Fuku is the curse laid upon the New World by the European colonizers, and the narrator believes Oscar's entire family is affected by their own personal fuku. This Dominican expression of national grief and struggle is deeply ingrained in history and culture, so one could argue that Oscar's life is shaped by the impact of this family curse. It is the source of his bad luck—why he can't get a girlfriend, why his sister is so unhappy, and a root of his deep depression. It all circles back to fuku, the reason why his family seems cursed, originating with Abelard and Trujillo.