You need to get out of the habit of treating people you heard cheated (which, might not even be true: this story sounds real, but people definitely make up false claims. For instance, my father, who cheated on my mother, made up false claims she cheated on him so people would hate her instead...) as inhuman.

This is really no different than how some people treat the homeless, drug addicts, etc. Or how people used to treat men and women, simply for being gay.

These people are all still human. Maybe one hurt you in the past: but that's no excuse to treat an entire group of people who made one mistake as inhuman monsters.

And, again, I've seen how people can abuse this tendency by spreading false rumors about someone cheating.