I think "The Secret of Family Happiness" is a great book for "unbelieving" spouses. You have an instant resource to explain the odd behavior of your partner. My (non-JW, activist) friend thinks this should be given to any woman thinking of joining the JW's. The requirements for women to submit should be offensive enough for modern women.
JW's too often treat their books like talismans or something, that if they could just get their "unbelieving" mates to finish a book, they will magically begin thinking just like them. The "Secret of Family Happiness" book sort of promises that if the "believing" spouse is kind, tolerant, and patient, that they will win over their spouse in time. It does not take any consideration that there may be individual differences. Like, say, someone like me who has studied the WT doctrines from a distance and found them wanting.
Not to mention that the book hasn't worked. JW's have just as many divorces as the general population.
Instead of droning through the whole book, why don't you cut to the chase and read together the advice for "divided households", (Chapter 11, Maintain Peace in Your Household). Discuss where your family is the same and different than the model offered here. Discuss your own fears and expectations.
Armed with the knowledge of how my husband has been advised, I remind him that he is a naturally good man, who makes good choices. He has not needed WT instruction to do that. Recently he's been trying harder to convince me to switch over to the Kingdom Hall. When he asked about my motives, I welcomed the conversation, but told him it would require work and a mutual review of Chapter 11. He's backed off. What I intend to show, if he mans up to it, is that I am NOT avoiding the Jehovah's Witnesses because he hasn't been kind or patient enough. I don't fit the mold, so there's another reason (it's not the truth). Is he ready to hear the reason?