Well True Ending 2 is an overall good ending in that you do fix your relationship and she proves that she is loyal to you and you alone. Some minor roleplaying to satisfy both character's fetishes but she doesn't cheat on you anymore or anything bad. Well part of her dumbness comes from her being groomed by the main antagonist for years and thus trusting the wrong guy. Palpatine did something similar to Anakin Skywalker, would you call Anakin dumb or a victim of unfortunate manipulations and circumstances beyond one's control? Remember that the blackmailer in this is pretending to be an innocent victim himself in all this and frames another, so she still trusts him and his words and advice. In a situation where she is scared and confused and unsure of what to do, she would naturally take the advice of of one of her closest friends, she has seemingly no reason not to, since they are both seemingly victims in this situation, in her eyes at least. Imagine being in a situation where you and a friend share a dark secret and this friend is the only person who understands your situation while you don't know what would happen if you would confide to an outside party, which is the MC in this case. She has no idea what the MC's reaction would be and she fears the worst case scenario, and her friend confirms that it would be a bad idea to tell the husband, and so on. Whenever she would gather the courage to confront the MC and tell him, the friend would intervene and sabotage it. So while yes, she is a bit stupid (but then honestly what heroine or protagonist doesn't have moments like that?), it's not completely her fault and she shouldn't be blamed as if she was. There is plenty of blame to go around (like literally every character), all things considered...