I haven't heard from you in a long time. I remember your sitch. Sorry to hear that you are having trouble controlling yourself. As I recall, you were very impressive at dealing with your husband during the crisis.
My situation was never as dramatic as yours. My H had his old girlfriend, and was planning to get rid of me and the kids and have a new life with her. Until I found out and ruined his plans. Then we went to a Retrouvaille weekend. They are offered all over the world. Check the website http://www.helpourmarriage.org to find one near you. The weekend made a world of difference to both of us. They taught us to communicate with each other in a fair and open way. And they taught us how not to talk to each other (saying mean things, name calling, bringing up the past, etc.). Spending an entire weekend talking to each other about our feelings and the things that are meaningful to both of us brought out the long lost love feelings. (They'd been lost about 20 years before.) The Retrouvaille weekend was the best thing we'd ever done for ourselves and our marriage.
But even after the weekend, when we were getting along very well, and enjoying each others' company, I was still haunted by his affair. I had nightmares, I had insecurity, I had his letters to her. That's when I started posting on this website. Talking about my insecurities here helped me to deal with it. It took a long time, and a lot of reassurance from him for me to get over his affair.
So you are not crazy. But you are out of control, and that is not good. You need help to get over this. The counseling is a good idea. And I recommend that you and your husband go to a Retrouvaille weekend. And keep posting here, and talk to us about your anger. We will understand. But sending him angry text messages is not the way to go. You know that.