So when I’ve found out about being cheated on, yeah, there was anger. But I also felt incredibly stupid, profoundly inadequate, embarrassed, betrayed. I wondered what I’d done wrong. Maybe it’s different if the person actually tells you instead of finding out in a way that blindsides you, IDK. But if the infidelity is a symptom of a larger relationship issue, which is how I read this letter, I’d sooner focus on that than the cheating. But you can do what feels right to you, LW. Good luck.