I don't know what to do? (Going through divorce)?

I had asked before what the steps were to the grieving process. I didn't know where I was until now. I have hit stage two. Very bad anger towards him and everything. I have people volunteering information and it's everyone. I have been told about every move my 22 year old husband and his Senior in highschool girlfriend makes. He has introduced her to family, shows PDA pretty much shamelessly. He won't admit anything and that seems to make me even more angrier. I saw the signs when we split up. Him being gone every night, her calling constantly. I feel like I am going insane. I can tell I want to lash out at any minute. I try to think of my daughter and how I don't want to be fighting with him for her sake. I am really getting worn down. I can feel my heart t in my ears at times and I feel like a damn ready to explode. It's just getting really bad. I don't know what to do with myself. I can't sit still and I am smoking like a chimney. What in the world do I do? (By the way I lived with him for three weeks before I found a place to go, so no longer living with him Thank God.)