Is a wife's maintenance negated if she is unjustly imprisoned, by analogy with the husband's inability to enjoy her company? And what about the dues of a wife whose husband has been absent for 18 months and refused reconciliation? Will she be rewarded if she forgives them to prove her lack of material ambitions, and is she mistaken in this intention?

As long as you are not refusing to go to your husband and travel with him, your maintenance (nafaqah) remains his obligation, and he is required to pay it. This is because his inability to exercise his right, if due to a reason originating from him, does not nullify his maintenance obligation. You have the right to demand that your husband pay the maintenance, or you may waive it and seek a khulʿ (divorce initiated by the wife). The court will rule on the matter based on the claims and evidence presented to it.