A man wrote to The Moneyist regarding his question of “fairness.” He and his wife are on their second marriages, and each has two biological children. The man has a million dollar inheritance from his parents, all of which he intends to pass to his biological children. His wife says that if she survives him, she intends to leave all of their common estate to her biological children exclusively. The man asked whether his wife’s intention was fair.

The Moneyist writer answered, in part:

A spouse’s inheritance is deemed separate property. So it is fair to leave it to your own biological children, if that’s what you want to do. Community or marital property, acquired during a marriage, goes to the surviving spouse. They can do whatever they wish with it.

That’s the purely legal answer. The writer, however, went on:

Your wife has made her plans clear. If she dies before you do, however, her kids could have a problem, because you plan to split the estate four ways, reducing your stepkids’ inheritance.

“Reducing your stepkids’ inheritance.” That distorts the matter. The man’s tacit plan, were he to survive his wife, to split the marital property four ways increases his biological children’s inheritance markedly from the complete shutout his wife plans for his kids while still leaving half the property to his wife’s kids. He could choose, per his legal control over the estate as the surviving spouse, to leave it all to his biological kids, shutting out his wife’s kids as she intends to do his.

The merits of the two spouses’ positions—what you and I, and The Moneyist, think is irrelevant. What’s fair is what the two spouses agree is fair.

There’s another lesson here, too, for blended families. The husband and wife, while they’re still prospective husband and wife, need to work this sort of thing out before they marry. If a disagreement over future plans for their prospective estate becomes a deal-breaker, it’s far better to know that in advance than after the marriage has occurred and then existed for some time. Of course, in the present case, there isn’t enough data regarding the timing of the man’s inheriting relative to their marrying to judge whether they could have worked this out in advance.