I’m not sure that sexual jealousy is a biblical concern. It’s a much more modern situation. When Abram’s wife Sarai goes off with the Pharoah, or Isaac’s wife Rebekah with Abimelech, and when Bathsheba heads back to Uriah, there seems not to be any male anguish, and none visited on the female. If some idea of spousal love is being born in these narratives, it is layered into a culture organized by thinking of life in terms of property. If a wife ‘cheats’ on a husband, a theft has occurred.
Your abortion theory is very interesting, and suggests the husband would have to be very careful — if the child was really his, he’d have slain his own progeny. Choices. But I think the decision once rendered would be accepted. Or for the husband to question the divine judgement would be a serious affront. God has spoken.
As often with biblical law, don’t we see it working with ordinary human motivations in unexpected ways? If you press a charge of adultery against your wife, you might kill your child, alienate her, and expose yourself to communal scorn. Does any woman want to marry you after that? The law is a prompt to self-reflection, and to maintenance of an ordered world. You wouldn’t want your wife to want to commit adultery, etc.