You’re not wrong, and I hate cheating as well especially when kids are involved. Thst makes it all the more dirty and an act of betrayal. But from ml’s perspective, it seemed like their marriage was very cold and sad and I think that person was just pointing out the fact that in a lot of contract marriages, it’s more like a business agreement than a real relationship or exchange of love so in that sense, it makes sense why the father looked so happy and smitten because he’d found someone who he actually had genuine feelings for, someone that made him smile like his own son had never seen. It’s not right, but as the other person stated, it didn’t even seem like the mother was that mad about the act of straying from the marriage in general. She seemed upset that it was with a predator. That alone tells you a lot about the state of their marriage/business arrangement.

Why did he find cheating beautiful? I'll forever hate my dad if that happens (it did happen and so many times as well lol, so hate is word that can't scale my hatred towards that fucker)
Or maybe I'm reading these chapters wrong...