One of the unforeseen issues with the MC and D's relationship is the fact D is an only child. Dating a girl with Only-Child-Syndrome is difficult to say the least. Not to offend only children, but not having siblings tends to make only children less willing to compromise and see issue from another person's prospective.
D was sheltered to the point of nearly being child abuse so this has made her more compliant however as she gains self-confidence this should change. By the end of the VN it would not be surprising if D became the dominant force in their relationship or abandoned the MC all together.
I think there would be less chance of this happening in a D-Only-Route where she is essentially still sheltered from the rest of the world by the MC. Pregnancy would be the logical outcome.
Of course DMD is a fiction. If Mr.Dots decided to he could have D end up marrying the El Presidente of Dounutstan, becoming a flamboyant first lady of the country and decades later have a talented British composer write a popular musical about her.
