Standard Islamic discourse on marriage assumes that its purpose is the regulation of sexual desire, and this is how I presented it in my post, Islam, Patriarchy, and the Recalcitrant Asexual Wife. However, it is worth noting that the Quran never states this in any place.
Given how detrimental the consequences of this sex-normative assumption can be for asexual Muslims, is there an alternative way of conceptualizing marriage in Islam that is less oppressive to asexuals?
I am definitely no scholar and cannot offer any definitive answers to this question. However, I would like to offer the following suggestion.
I believe that the following verse is the clearest statement in the Quran about the purpose of marriage:
And from [God’s] signs are that He created for you from your souls, spouses, that you may be tranquil with them, and He decreed between you all love and gentleness. Surely in that are signs for a folk who contemplate. (Quran 30:21)
The early Sufi authority Abu Talib al-Makki took a very similar position:
God has decreed neither marriage nor celibacy… But he has decreed integrity of heart, preservation of faith, a soul at peace, and the execution of commands needed for these… And if one’s healthful condition, integrity of heart, and peace of soul reside in celibacy, then that is better for him, since these are the things that are desired of marriage. If one can reach these without marriage, then celibacy causes no harm.
I would go a step further and suggest that we recognize that any relationship that brings tranquility, love, and gentleness fulfills the purpose set out in Quran 30:21 for marriage, even if the relationship does not involve sex.
Another passage that I feel is important comes as part of a verse that sets out the basic procedure of marriage:
...And there is no fault on you in what you make for mutual satisfaction by it after the required [bride-gift]. (Quran 4:24)
(The earlier part of the verse establishes the requirement for the husband to provide a gift (the mahr) to the wife as part of making the marriage.)
Rather than designating a spouse as recalcitrant because they don't meet an externally-imposed standard of providing sex in the marriage, why not let the partners agree together on the terms that will give them mutual satisfaction, and only invoke recalcitrance (nushuz) if their specific agreement is violated? If the couple have made a mutual agreement to not have sex in their marriage, then under my proposed interpretation, this becomes the standard against which their relationship is judged, rather than a special exemption to a uniform rule of compulsory sexuality.
This is not so much a change to any of the rules governing marriage as it is a change to the conceptual framework in which marriage is understood. By changing this framework, we can avoid making sex-normative assumptions that end up stigmatizing asexual Muslims who are unable to provide sex and opening them up to potential harm.
Incidentally, the above understanding about the purpose of marriage and the priority of the couple's mutual agreement would not just be liberating for asexual Muslims, but would offer greater freedom in marriage to allosexuals as well. Everybody benefits when we give people greater autonomy rather than imposing uniform assumptions on them.