“And it is not lawful for you (men) to take back (from your wives) any of your Mahr (bridal-money given by the husband to his wife at the time of marriage) which you have given them, except when both parties fear that they would be unable to keep the limits ordained by Allaah (e.g. to deal with each other on a fair basis). Then if you fear that they would not be able to keep the limits ordained by Allaah, then there is no sin on either of them if she gives back (the Mahr or a part of it) for her Al-Khul‘ (divorce)”
The Khulla is the right of the woman in Islam to ask for an annulment of her marriage in order to dissolve it. “Khula’ means the separation of the wife in return for a payment; the husband takes the payment and lets his wife go, whether this payment is the mahr which he gave to her, or more or less than that” (Islam qa).
Why is it then that a khulla appears to be the right of a man because he ascertains whether she can have an annulment or not? The argument here is not as to whether the wife has justification to end her marriage or not, but whether she has the means.