Character Analysis
Husband #4 gets a separate description from the Wife's first three husbands because, apparently, he does not bow to the Wife quite as easily. Instead, he keeps a lover, a situation which necessitates a different approach to dominating him on the Wife's part: the Wife makes him think that she is cheating on him, and the jealousy drives him crazy.
In addition to providing the opportunity for the Wife to describe another of her methods of domination, the situation with Husband #4 is also the first intimation we have of the Wife's vulnerability, for she admits to being upset that her husband takes delight in another woman.