Is it permissible to supplicate for the return of one's husband after divorce, or should divorce be considered divine decree and destiny and accepted as such?

There is no harm in supplicating for a man's healing and for the two of you to be reunited in marriage once again, as there is no sin or transgression in such a supplication. Belief in divine decree (qadar (definition)) does not negate supplication (du'a), for du'a is a means to repel affliction and attract mercy, and it is itself part of Allah's decree. We advise you to strive diligently in supplicating that Allah grant you a righteous husband and to entrust the matter to Him, for Allah knows best what is good, and divorce is not evil in all circumstances.