Like I said, what if the couple feels the children can be brought up in a better environment with a more hopeful future?
Isnt adoption a viable, prolife option?
While it might be an excellent thing to go for adoption as a good last option or to “farm out” children temporarily in a case of great need, a couple should not be hopping into bed planning that any children conceived by their union will be placed for adoption. As people have mentioned, the education of children is just as much a duty as their procreation and responsible parenthood is explicitly encouraged in Humanae Vitae.
vatican.va/holy_father/paul_vi/encyclicals/documents/hf_p-vi_enc_25071968_humanae-vitae_en.html
Have a look at the section on “responsible parenthood.”
“With regard to man’s innate drives and emotions, responsible parenthood means that man’s reason and will must exert control over them.”
“With regard to physical, economic, psychological and social conditions, responsible parenthood is exercised by those who prudently and generously decide to have more children, and by those who, for serious reasons and with due respect to moral precepts, decide not to have additional children for either a certain or an indefinite period of time.”
“Responsible parenthood, as we use the term here, has one further essential aspect of paramount importance. It concerns the objective moral order which was established by God, and of which a right conscience is the true interpreter. In a word, the exercise of responsible parenthood requires that husband and wife, keeping a right order of priorities, recognize their own duties toward God, themselves, their families and human society.”
“From this it follows that they are not free to act as they choose in the service of transmitting life, as if it were wholly up to them to decide what is the right course to follow. On the contrary, they are bound to ensure that what they do corresponds to the will of God the Creator. The very nature of marriage and its use makes His will clear, while the constant teaching of the Church spells it out.”
The sort of scenario you mention (unlimited sexual union, no parenting) is pretty much unknown unless there is a serious problem with the couple (whether mental illness, other mental deficiency, or serious substance abuse problem).
There has been at least one case on the forum where a married woman wanted to place a fourth and fifth child for adoption, but there seemed to be fairly serious mental health issues at play.