I think u missed the point. But before that, anyone would be pissed if ur husband kissed another woman on the mouth. They both had insecurities they had to grow up from, hers were more deeper than his. Like she said, she was constantly trying to protect herself from being hurt by others, since she never felt like she belonged. It was definitely frustrating seeing her running away from her problems instead of working to fix them, but she was able to realized it once she got away and got a different perspective in life. Sometimes that's all it take, I think this did a good job at showing that. The characters showed growth, although it could have been stronger growth and much clearer if this wasn't a one shot.
Urgh the female lead ヽ(`Д´)ﾉ I know that she run from his husband because of his mother and another woman crash at the apartment but she so selfish knowing her husband marry her even tho she orphaned and just graduated not prestigious school and also he already say he lonely but what she doing ┑(￣Д ￣)┍ after that play victim and while Male lead family have some illness she just fucking run away Σ(っ°Д °;)っ whyyyyyyyyyyyyyyyyyyyyyyyyyyyyy.. know I understand why she orphan