To have coitus other than to procreate children is to do injury to nature -
Clement of Alexandria
But I wonder why he [the heretic Jovinianus] set Judah and Tamar before us for an example, unless perchance even harlots give him pleasure; or Onan, who was slain because he grudged his brother seed. Does he imagine that we approve of any sexual intercourse except for the procreation of children? -
St Augustine
For thus the eternal law, that is, the will of God creator of all creatures, taking counsel for the conservation of natural order, not to serve lust, but to see to the preservation of the race, permits the delight of mortal flesh to be released from the control of reason in copulation only to propagate progeny -
Jerome
They exercise genital acts, yet prevent the conceiving of children. Not in order to produce offspring, but to satisfy lust, are they eager for corruption -
Epiphanius
If you can explain how these quotes apply to ABC but not NFP then my hat’s off to you.