Emmanuel
remedy has been widely accepted in the Church for a long time. People
seem to think that the brother-sister relationship avoids objective sin
under the law. That opinion deserves a closer look.
III. The “Brother-Sister” Relationship
Of course, infidelity means more than simply a sexual union in
violation of one’s marital commitment. The Catechism of the Catholic
Church notes that “Christ condemns even adultery of mere desire”
(2380). When a husband flirts with someone else’s wife, or romantically
caresses her, or becomes “emotionally involved” with her, or dates
her on the side, everyone would agree that those constitute acts of
infidelity. They adulterate the marriage. Consider this situation: What
if a man were to separate from his wife and move in with another
woman? They marry civilly and hold themselves out as husband and
wife but do not have sexual relations.
Certainly such an arrangement would constitute a colossal act of
infidelity against the wife — indeed, even a mortal sin. Yet that so-called
“brother-sister” arrangement is now allowed by the Church where a
second marriage cannot simply be broken up without causing serious
harm. Catholics rightly seem unfazed by the arrangement in view of
the fact that children need to be brought up in something resembling
normal family life. Yet this merciful answer to such a dilemma does not
nullify the fact that a prior marital bond is violated in that relationship,
which continues even after the children have grown. 14
Those who claim that the Church cannot allow an irregular marriage
to remain as it is have not considered the brother-sister relationship
itself as already an arrangement that adulterates the original marr