I may be writing out of turn, but your husband's behavior concerns me somewhat. I wish that he had shown deeper understanding of what feelings you might have in response to the new GF. If you were accurate in describing his preoccupation with her, then I would wish that he had instead taken special care during that stressful time to show that YOU are the most important woman in his life.
I personally did not feel as if I had much control of how the situation was approached.
When you don't have control in a central area of your life it's not unusual to feel frightened, angry, depressed. I agree with others: you should find a way to make your wishes heard and have your needs met -- your need for loving security in particular.