My anger is boiling over.

How you are feeling is probably quite a normal response to all the difficulty and pain you seem to have been through. No one can blame you for feeling that way about your ex. However, you can be blamed for how you act upon your feelings. If you're feeling that violent, you may end up doing something to your ex that you will regret later. My advice is to distance yourself from her. Physically, emotionally. Whatever you need to help the 'monster' in you calm down. Stay away from her until it is safe for both of you to do otherwise.

I agree with the answer above, however if it doesn't help try to find someone and spend time with them so that you can get your mind off your exgirlfriend. Perhaps this someone will be the one who you'll fall in love with and think about the past and laugh about this anger you have right now.If that doesn't help either then contact a therapist who you can talk to and pour all your anger to without hurting anybody. You'll get help to control yourself and avoid being a monster.I hope this helps. Good luck!

Do not let anger consume you. The malice you have for your girlfriend is a result of pain. And to let it get to this point, you're not hurting her, you're hurting yourself. When the anger started building, you should've distanced yourself immediately. That usually helps--and by distance yourself, I mean, you have no source of contact, you don't have any way of getting an update on her new life, and you are doing something that you love to occupy your mind. In fact, it sounds like she's practically rubbing it in your face; she wants you to react negatively to what just happened. When a woman wants to mess with you, they'll mess with your psych (though don't say I'm generalizing, I'm just saying that this is one way we get our revenge). So get away from her, calm down, and know that you WILL find someone else that you deserve. You got this! Don't let someone's actions pull you down! Let this fuel your determination to move on and get something better! :)