I have seen some commentary about the “use” of the other that is almost angelistic, to use a word that does not appear in my word processor dictionary. There is still the reality of concupiscence, the reality of those feelings that stimulate one or both spouses to desire the marriage act. The Church’s moral theology has always recognized the truth in 1Cor 7:1-9. That is, to put it briefly, that one of the purposes or legitimate functions of the marriage act is the relief of concupiscence. Here I think it is important to distinguish between the invitation of one spouse as contrasted with a demand. And, of course, the invitation should be in the context of a mutually helpful relationship in every part of their domestic household. My point is that some of the talk against “using” the other spouse seems to be denying the moral acceptability of admitting that if it were not for these feelings the initiating spouse would not be thinking about and desiring the marriage act. There are many ways that spouses can express their self-giving love for each other, many of which are appropriate also for siblings, cousins, and neighbors. But the feelings that lead to desire for the marriage act are not exactly the same as, say, the feelings of appreciation that lead to helping with the housework, etc.
John Kippley
Sex and the Marriage Covenant