"It is still not an excuse to hide her feelings and not tell me that she was upset, and it most certainly doesn't justify falling into the arms of our friend's fiancee."
In her mind it does. She felt you were controlling her life, so she found comfort in someone who had no expectations on her whatsoever.
"So I have come to the stark realization that even if she had come back to me, I couldn't trust her, I couldn't trust that she was being honest with me."
Yes you could. It comes with understanding things from her POV.
"She was a completely different person to my face than she was to others. What did she have to gain from that?"
She treated you differently because she didn't trust giving you her feelings.
"I will never understand why she would hide her true feelings from me."
Because she didn't trust you enough to open up. Women just want to be heard and not told how to make something better.
"I also have no doubt that she will end up in this same situation 5 years from now if not before, and that makes me sad for her."
Maybe. However, the realization is that if she finds a man who knows how to listen to her the RIGHT way, then she won't. Point is that you can be that man. You just have to "listen" to what she says rather than just hearing.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.
