Vayikra 18:20:
ואל אשת עמיתך לא תתן שכבתך לזרע לטמאה בה.
Why does the verse mention “seed”, and why “Amisecha”, unlike the other Arayos prohibitions (including the mention of adultery’s punishment itself elsewhere)?
I think the answer is simple. In case the adultery produces results, it is also a grievous sin against your fellow man who will give his time and money and food and patrimony to one who isn’t his own lawful heir.