I Kissed my ex boyfriend!!! Did I make a mistake?

Well, I think this could be a sign that he is trying to change for you so that you two could get along again. Because of these anger issues you speak of, I would recommend that you be careful if you plan on getting back with him because there is a chance that he could hurt you again. If he makes you happy and whole, then stay with him because your happiness is what matters. If not, then it would be in your best interest to find someone who does so that you can make sure that you are not hurt ever again.