It's because it's so extremely out of character that the obsessive, yandere who can't stop thinking about his spouse suddenly seemed to completely forget Hardy even existed just to sleep with someone he thought was attractive after doing everything he did to have Hardy in the first place.
It actually plays EXTRA BAD with the drug thing because it's like "so you drugged him, did all this other stuff bc you were obsessed, just to completely forget your wife exists? Not even a thought about Hardy?"
It's the total dissonance. I can accept that he, as an obsessive character, did bad things to monopolize Hardy (not things I think are okay to do fyi but it at least lines up with his character). But it's actually LITERALLY unbelievable to think he'd cheat.
Y'all not okay with Abel cheating but is okay for Abel to be drugin hardy. I hope they're not endgame i hate Abel by the way he to pushy.