Is the husband to be considered an oppressor or merely exercising his legitimate right to divorce, after concealing sexual dysfunction before marriage, and then arbitrarily divorcing his wife without her knowledge, subsequent to her treating him with kindness and enduring patiently with him?

The husband should have reciprocated good with good, for preserving kindness and acknowledging favors is the characteristic of noble people, as Allah Almighty says: "Is the reward of good [anything] but good?" Therefore, the husband is not an oppressor merely by divorcing his wife. The original ruling on divorce is that it is permissible, but it is disliked to resort to it without need. And perhaps in this separation there is a good that Allah willed. So let her forget the past and start her life anew, and ask Allah for a righteous husband, for Allah Almighty says: "But if they separate [by divorce], Allah will enrich each of them from His abundance. And Allah is ever Encompassing and Wise." And there is no legal impediment to seeking a righteous husband and proposing herself to him within the bounds of Islamic etiquette.