s be the breasts that satisfy you,
A DESERT WELL
Of course this is a patriarchal society, but it is unclear what sort of marriage custom this envisages. The “wife you married when you were young” is usually an indication of polygyny of some sort, in which a man might have several wives. In this case, the wife mentioned seems to be the only one. The man is therefore choosing an extra marital affair with a married woman, here called separate or strange. It’s possible that she is not Jewish.
Clearly the wisdom here is concerned for the neglected wife and with her husband, rather than with the disruptive woman. The author supposes that the affair will end badly, and horror of horrors, cost the offender a lot of money! The cruel person may be the woman’s husband or owner.
However the clear message is that such affairs are folly, bringing no good and much ill.
The errant man is reminded that his wife is attractive and his right sexual partner. The true wisdom here is that sex is often not really casual but binds people together, in faithful love or in a looser relationship, and has consequences in people’s lives. In the context of marriage sex is seen as good and delightful, as is faithfulness; but when faithfulness is about to be forgotten, common sense can come to the rescue.
The woman is blamed because she invites foolish male behaviour, but she is at least given the dignity of not being a victim: she wants the man. The wisdom expressed here is conventional, but is not over serious, casting a shrewd eye on human folly, and recommending something more likely to give happiness.