The answer to the question, “Who decides how to spend the money in a marriage?” depends heavily on what you think a marriage is. So, what is the nature of marriage?
One foundational truth about the nature of marriage is that two people become one entity, one living thing. This is what Ephesians 5:31 tells us—“FOR THIS REASON A MAN SHALL LEAVE HIS FATHER AND MOTHER AND SHALL BE JOINED TO HIS WIFE, AND THE TWO SHALL BECOME ONE FLESH.”
Many problems in marriage would be greatly reduced if both spouses could get a hold of this truth. Once you became husband and wife, you ceased to be simply a man and a woman. Two separate people became unified through marriage; they are a unit.
You became one with someone else. There is both a unity and diversity in your relationship. It is a mystery on par with the Trinity. Two persons in one marriage—the two are equally human and equally precious; yet the two are distinct from one another.
Decisions are made with this truth in mind: we are two in one, so all blessings and challenges are ours to handle.
The husband doesn’t decide that he needs a new suit. You both decide that money needs to be spent to clothe him this month. The wife doesn’t decide she needs a new car. The two of you decide it is best to get her a better car. Or not.
Only it must a joint decision. This of course becomes a sticky point when agreement on a particular issue becomes scarcer than ice in the Sahara. This is, in part, why Paul instructs men to love their wives and women to respect their husbands.
Your needs and wants become his needs and wants. And vice versa. Husbands must see that they are serving and sacrificing for their wives. Wives must see that they respect his desires. No one trumps the other.
Yet, when the two can’t agree on what to do with the money, someone has to break the tie. Who that person is should be mutually decided ahead of time. Given that men are called to be the head of the marriage, it should normally be the man who makes the final decision. But this is not always wise.
If a spouse has a track record of poor financial decisions, take someone with a gambling addiction as an example, that spouse should not be making the final decisions. He or she should be consulted, but should not be the decider. If this is the husband, then he should delegate the lead role on financial matters to his wife.
Barring any special circumstances, man and wife make decisions as equal partners. In doing so, they reflect the glorious likeness of God.