If done with modesty, it would not be considered inordinate (not ordered).
It would only be considerd morally disordered if such pleasure was sought for itself, isolated from its procreative and unitive purposes. It is “ordered” desire, otherwise.
Does that mean that when one desires their spouse, they must also desire the birth of another child? No. That’s not what “isolated from its procreative purpose” means. The Church teaches:
“…those who in exercising it [conjugal act] deliberately frustrate its natural power and purpose [procreation and unity between spouses] sin against nature and commit a deed which is shameful and intrinsically vicious.” (Casti Connubii, 54).
“…* If therefore there are well-grounded reasons for spacing births, arising from the physical or psychological condition of husband or wife, or from external circumstances, the Church teaches that married people may then take advantage of the natural cycles immanent in the reproductive system and engage in marital intercourse only during those times that are infertile, thus controlling birth in a way which does not in the least offend the moral principles* which We have just explained. (20)
Neither the Church nor her doctrine is inconsistent when she considers it lawful for married people to take advantage of the infertile period but condemns as always unlawful the use of means which directly prevent conception, even when the reasons given for the later practice may appear to be upright and serious. In reality, these two cases are completely different. In the former the married couple rightly use a faculty provided them by nature. In the later they obstruct the natural development of the generative process. It cannot be denied that in each case the married couple, for acceptable reasons, are both perfectly clear in their intention to avoid children and wish to make sure that none will result. But it is equally true that it is exclusively in the former case that husband and wife are ready to abstain from intercourse during the fertile period as often as** for reasonable motives the birth of another child is not desirable.** And when the infertile period recurs, they use their married intimacy to express their mutual love and safeguard their fidelity toward one another. In doing this they certainly give proof of a true and authentic love.” (Humanae Vitae, 16).
The “procreative” purpose is where most have difficulties.
Clearly, if a spouse were to demand sex, forcing themselves upon their spouse, for example, this would be a rather non-“unitive” act for a spouse. In such a case, the other purpose of marriage and conjugal acts, the “unitive,” would also be isolated, and therefore disordered.
Thus, sexual desire is disordered if engaged contrary to unitive purpose of marriage, or when one acts to deliberately frustrate the intrinsic relationship of conjugal acts to the procreation of human life.