Broken trust, what to do?

It has been 10 months of my marriage and before that we were in a courtship for a year. In the beginning of our relationship we had a equation that we will never break each other's trust. Since then he knew all my stories inside out, my boyfriends, how did I start and how did it end. He never talked about his relations and said he will talk about it later. I in the meanwhile forgot. He has a habit of reading my phone and mails. I was never like this but gradually I became curious and started reading his. I read a few things which I asked him about his past relationship, he lied. Then a few months back I got to know about his association with his sister's bestest buddy, who was also present on my day of engagement. I can't stand this as I had a terrible past of close ones betraying. Why didn't he tell me this. This have become ugly now, I keep visualising him with her as there are pictures of him with her and as I in my real life have seen them standing together in my presence. Now I have lost respect for my husband and feel like I don't love him. Though he is very caring and a good man but I am not able to stand him as this is not less than an extramarital affair to me. I am not able to work, sleep or interact with people well. What should be done in this case, any suggestions?