The court treats his actions as "cruel acts" and "adultery". If she files the divorce case and prove his adulterous acts in the manner prescribed by law, then she will get divorce.
Maintenance amount does not depend upon his adulterous act. It depends upon his earnings, his expenditure, his responsibilities and his living style and her income, expenditure and living style. The court considers all these things and fix the maintenance amount between 1/3rd to 1/2 of his income, if she is not earning on her own.
She has been insulted. She wants to take revenge. Hence, she is fighting. You also may agree that in our society a divorcee boy and a divorcee girl are not treated equally and the girl is always blamed for divorce and alway people fear to marry a divorcee girl, even though there is no mistake on her part in her earlier matrimonial life. To face difficult situations in future, she wants proper compensation and it can be given to her only through protracted legal battle, wherein it would be proved that divorce is granted only due to adultery of her husband and no fault of her . If she accepts for mutual consent divorce, you may not properly compensate her. Hence, this legal battle.