Re: Khula , cheating husband and Haq-e-Meher
If this is based on a real situation, you should really consult an aalim.
In terms of being entitled to mahr - she was entitled to it just by virtue of being married to him and particularly if they consummated the marriage.
When khula takes place, your question should be more about does she then have a right to hold on to her mahr. If the amount they’ve agreed on is less than the whole amount of the mahr, she is entitled to the balance.