Mina and Jonathan Harker are the only real married couple in Dracula. Yet the idea of marriage comes up pretty frequently. The questions of who should have the power in a marriage, and what the roles of the husband and wife should be, are asked and answered in various ways, both in Mina and Jonathan's relationship and through the discussions of other characters.
Arthur Holmwood interprets the blood transfusion between himself and Lucy as analogous to a sexual consummation of their marriage.
Mina's victimization at the hands of Dracula is interpreted by the characters as a kind of rape – Mina is not allowed to sleep with her husband until after Dracula is killed and her sexual purity is restored.