I have to agree with Derbylicious, remember, it is in your wife's best interest to see your exgf behaviours as manipulative, because then she feels it is easier to excuse your behaviour, it isn't particularly insightful, it is just easier and very, very human to do so. Do you really want to cast your ex as an evil person to help you recover from your feelings? Or do you want to learn to grow and accept the path you chose to take? Including allowing someone else to dictate your other relationships?
You'll have to recover from this relationship and examine whether Polyamory is the correct path for your future.