If the infertility of one spouse is confirmed, is it permissible for the other spouse not to marry out of loyalty, or is that considered a violation of Allah's sunnah regarding procreation?

If a man ascertains his wife's infertility, he may choose to remain with her. Alternatively, he may marry another woman seeking offspring, which is preferable due to the general evidence encouraging it, such as the Almighty's saying: "And seek what Allah has ordained for you," and the Prophet's (peace be upon him) saying: "Marry the affectionate and fertile woman, for I will boast of your multitude before the nations on the Day of Resurrection."

Similarly, if a woman ascertains her husband's infertility, she may choose to remain with him and be patient. Alternatively, she may seek a divorce from him due to the harm she experiences from his infertility.