Does swearing not to approach unless the wife desires it constitute Ila'?
General Chapter
Al-Mughni
Book of the Oath of Abstention (Ila')
Primary text
If a man says, "By Allah, I will not approach you until you will it," this is treated the same as saying, "except with your consent" or "until you desire it," and it does not constitute Ila'. This is because he has restricted himself by oath from intercourse except upon her desire, making it akin to the case where he swore abstinence except with her consent. Furthermore, he suspended the oath upon the existence of her will, similar to suspending it upon the will of another person.
Supporting text
Abu Al-Khattab stated that if she wills it in the same sitting, he does not become a Muli; otherwise, he does. Companions of Al-Shafi'i hold that if she wills it immediately after his statement, he does not become a Muli, but if she delays, he does, as they consider the will to be immediate and thus missed through delay.