LedRock:
Then you don't love such a person. If men and women should be killing their cheating partners, do you think humans will still exist.
Well that is the problem if those who are interested in marriage.

Romantic love, as u define it, does not exist. So let’s be clear about that. Possession is always part of it. Hence “a woman scorned...” Scornful preference for someone else magically turns it to hate.
As for the rest, your concern is to neatly solve your problem not wether humans will still exist