I think I get your point, and the misunderstanding may be that by "nature as living beings" I went beyond just humans. For the vast majority of living things, avoiding reproduction seems, to me, unnatural, hence it would go against our very nature.
Now, from a anthropocentric view of this contraception is quite natural as, like you well explain, it let us satisfy biological urges while reducing the risks and potentially undesired side-effects of them.
The point that I tried to make was that being for or against "our nature" does not feel, to me, to be a good measure of mental health.
