A woman ought to tell her husband everything—don't you think so, dear? (5.6)
Lucy and Mina like to exchange ideas about all kinds of things, especially (since they're both engaged) the roles of husbands and wives.
Men like women, certainly their wives, to be quite as fair as they are; and women, I am afraid are not always quite as fair as they should be. (5.6)
Lucy idealizes men: She thinks that they're more "fair" than women are.
Why can't they let a girl marry three men, or as many as want her, and save all this trouble? But this is heresy, and I must not say it. (5.11)
This is a pretty scandalous thing for Lucy to say! She's basically advocating polygamy here. This is what we're talking about when we say that Lucy is naturally more sexual than Mina is—Mina would never, ever suggest that it would be awesome to have more than one husband.
I supposed that we women are such cowards that we think a man will save us from fears, and we marry him. (5.7)
Lucy makes a generalization about all women—she thinks that women marry men to run away from their fears, thinking that the man will "save [her] from fears."
Mina Murray Harker
I must stop, for Jonathan is waking—I must attend to my husband! (9.6)
Here's a taste of Mina's ideal of marriage—"attend[ing] to [her] husband." She's such a tender, maternal person that she nurtures everyone.
I feel very solemn, but very, very happy. Jonathan woke a little after the hour, and all was ready, and he sat up in bed, propped up with pillows. He answered his "I will" firmly and strongly. I could hardly speak; my heart was so full that even those words seemed to choke me. (9.4)
Mina hardly sounds like a glowing, blushing, happy bride. She says she's happy, but she almost seems to insist on it too much. Even the words "I will" seemed to "choke" her. Isn't she happy to be married to Jonathan?
"You know, dear, my ideas of the trust between husband and wife: there should be no secret, no concealment." (9.2)
This is Jonathan Harker's ideal of marriage. Of course, he's the one who breaks this ideal when he stops keeping Mina in the loop about their fight against Dracula. And look what happens! She gets bitten.
Dr. Abraham Van Helsing
"If so that, then what about the others? Ho, ho! Then this so sweet maid is a polyandrist, and me, with my poor wife dead to me, but alive by Church's law, though no wits, all gone—even I, who am faithful husband to this now-no-wife, am bigamist." (13.85)
If Arthur "married" Lucy by giving her his blood, then she's married to four people. Van Helsing finds this hilarious, especially because he's already married, and his wife is insane. Wait, why is that funny?
Arthur was saying that he felt since then as if they two had been really married, and that she was his wife in the sight of God. None of us said a word of the other operations, and none of us ever shall. (13.78)
Arthur thinks that giving a blood transfusion to Lucy is the same as "marrying" her. Is that weird?
On the bed beside the window lay Jonathan Harker, his face flushed and breathing heavily as though in a stupor. Kneeling on the near edge of the bed facing outwards was the white-clad figure of his wife. (21.42)
It's important that Mina doesn't get victimized by Dracula just anywhere—she gets bitten on her marriage bed. That's like the holy of holies of the British home.