Is it time that I should I just divorce and move on with my life?

When my wife and I were dating, the second we hit a rocky patch she cheated on me. I forgave her because I was so deeply in love with her, I have done my best to try to truly forgive but I have not been able to. A week after we were married, I discovered that she had been talking to one of her ex-boyfriends online and had even premeditated going back home to hook up with him under the guise of going back home for a relative's birthday. Since then, one of our children died in an accident in our home and I find myself (mentally) blaming her for what happened. I really do not enjoy her company, she has nothing to offer in a conversation anymore, she has zero ambitions and has stopped growing as a person. Everything that I do not like about her I start to find myself doing because I am conforming to her way of life. She is a slob who is extremely indecisive and she has very low self esteem which is starting to rub off on me as well. She is nothing like the person I knew before we were married. I still love her, but I am not in love with her. Is it right to divorce? Is my happiness worth anything? Should I not divorce just for the children?