There is never a justification for cheating. And what’s more, if it’s in a story, that only strengthens my point: how are you supposed to feel empathy or connect emotionally with characters like that? Unless you have a paraphilia or are trying to justify yourself, of course.
You shouldn't gaslight yourself; that just messes with your mind and makes you start justifying everything and seeing the bad as good.
I watched up to episode 50, but it just left me feeling uncomfortable, and I didn't connect with the characters.