1,495. Making Kiddushin When Another Man's Kiddushin is Already Pending

Hilchos Ishus 7:10

Let’s say that a man consecrates a woman on the condition that he gives her 200 zuz within 30 days. If he gives her the money within the allotted time, marriage is effected; if the time passes and he has not done so, then marriage is not effected. If he tells her, “You are consecrated to me through these zuz after 30 days,” then marriage is effected after 30 days even if she spent the money in the interim. If either of them changes their minds within the 30 days, then marriage is not effected.

Hilchos Ishus 7:11

If another man consecrates the woman within those 30 days, marriage is effected with that second man. Since she was not yet married to the first man, the second man’s kiddushin is effective. Therefore, once the 30 days have passed, the woman is already married. It’s therefore as if the first man tried to consecrate a married woman, which is ineffective.