To me the “Why can’t they let a girl marry three men” isn’t about Lucy being romantically in love with all three suitors (which we know she isn’t- Lucy about Arthur on 11th May “But oh, Mina, I love him; I love him; I love him!”) nor about her literary asking for three husbands (which she doesn’t- Lucy about Quincey on 24th May “Oh, why must a man like that be made unhappy when there are lots of girls about who would worship the very ground he trod on? I know I would if I were free—only I don’t want to be free.”), its about having so much empathy that any form of pain someone experiences you want to ease, about having so great a heart that your feelings are overflowing you, that you only wish the absolute best for the other. Most of us must have had moments when we wished our dearest friends the best in the world, but oh, imagine if that happiness depended on you but you couldn’t give it? Anyone with a heart would feel bad, although at no fault at all…
Put that in contrast to Dracula, who masks his own hunger as “love” (it seems pretty clearly to be established that vampires in this novel use expressions like “kiss” and “love” as substitutes for far darker actions), binding and imprisoning anyone who peeks his interest and who could make his days a bit less dull and his life a bit longer.
Dracula dresses up his selfish desires in what the world would consider “marriage”, gaining only slaves he is forced to endure.
Lucy gives her love so freely that she not only gains a fiancé who kisses the ground upon which she walks, but also two friends who’s friendship for her will last beyond her life.