Like pinkflamingo, I cared about my T. I made excuses for her. I also have low self-esteem. So when there were issues, I assumed it was me because I was the one with mental health issues. Maybe it's because of my issues I looked past her faults? Maybe it's because I'm unhealthy? But it doesn't mean I am or anyone else who has done this is "bad" or "stupid". We're in therapy for a reason. So while you might not understand, many of us do. Count yourself lucky that you never experienced the betrayal or even the level of attachment (or for some transference). It hurts so much.