Reality- why the need for defiance? Why is she feeling oppressed for the consequences to her actions? To me that doesn't give a whole heap of credibility to remorse, but regret. Why was there no communication? Communication tends to be a biggie with those that cheat, why not come to you like an adult and say she was needing a social outlet and would you feel safe if she opened a twitter account if you had all the login details? This is what concerns me
- she hid it, deleted the emails from her inbox and didn't tell you openly
- her reason for doing it was defiance
- she got defensive about it, didn't own the behaviour as not ok straight away
- her previous affair was enabled by technology
This all screams wayward behaviour to me. You are not over reacting, at the very least it's some proof that perhaps she hasn't learnt a whole lot from the experience. I'm sorry you are going through this.