True. No argument here.
"...and abstaining from intercourse is not the only moral choice to doing so."
If speaking of veterinary medicine or animal husbandry, you are right. There is nothing particularly sacred about animal breeding, and their reproduction can be controlled by "spaying" or "fixing" or snipping their whatevers.
Why? It's because animals are instinctive and act appropriately to their animal nature: they can't control their breeding behavior or conceptualize any transcendent significance or sacred value for the how's, why's or with-whoms of how they mate.
If speaking of humans, you've got a fundamentally different situation, since humans can both control their behavior AND conceptualize transcendent values.
The reason why human sex requires special, even sacred handling, is that we believe it has a sacred purpose: the expression of sacred marital love and the procreation of beings which personally bear the image and likeness of God.)
Unless you get the "sacred" part, I seriously think it's pretty hard to get the "ethics" part.
Hence acting intentionally against love or directly disabling the procreative potential of the act, is morally problematic for human beings.
As a general rule in ANY kind of medical ethics (not just sexual ethics) it is wrong to act to directly disable a human organ or system, when this disabling is your intent.
For instance: Judicial maiming is unethical. Maiming by cultural choice (e.g. female genital mutilation) is unethical. Transgender body modification is unethical.
BTW, and tellingly, Muslims would disagree with that; this is because Islam teaches no regard for inherent or intrinsic human dignity, has no particular respect for Natural Law, and has no Scripture that tells them they are created in the image and likeness of God.}
But back to our theme of ethics: removing someone's eyes or limbs as sheer preference-based elective surgery is unethical. (I am speaking of "treating" people for Body Dysmorphic Disorder (LINK) --- where an emotionally disturbed person wants to cut off a healthy limb or remove a healthy eye or other organ, not for the therapeutic purpose of removing a diseased body part, but simply for elective choice). That is unethical.
Unethical for humans, but not for animals.
The reason it's unethical for humans, but not for animals, is because animals' bodies are of a lower order than ours. They can be owned, disposed of, used, treated instrumentally.
Human bodies are not to be used in exactly the same way, because we are not absolute owners even of ourselves. We are image-bearers of God.
Hence human dignity requires that we not treat our bodies as pure objects, but as persons whose design is both significant and providential.
And that includes sexual design.
“Hence acting intentionally against love or directly disabling the procreative potential of the act, is morally problematic for human beings.”
Outiside of marriage I would agree, as “sexual ‘love’ “ is the ONLY purpose likely being served. Within a loyal marriage union I personal do not believe the couple is commiting any sin. They do not have to leave pro-creation to mere chance, anymore than the creative acts of G-d are just accidents of His creation with no higher intelligence behind them.
Reading and posting in this thread has given me an urge to get off this computer and awaken the wife...