What about divorcing the wife and conditioning it on infidelity, without informing the wife?

If a husband stipulates that his wife's divorce is contingent upon her infidelity, then the divorce takes effect upon the occurrence of infidelity, even if the wife is unaware of the stipulation. However, if the wife is someone who would be concerned by this stipulation, and the husband intended to inform her but she did not become aware, then some jurists hold that the divorce does not take effect. It is preferable for the husband to inform her of this stipulation so that she may be cautious. One must beware of being lax in uttering pronouncements of divorce.