I know this is hard and you are miserable... contact some friends... do something, get out of the house... but most of all-- be kind to yourself and know that only you will really be able to put yourself out of your misery.

Be patient... it takes time.

I remember how I felt at that point. I would cry so long and so hard I to wanted someone to take me out of my misery. There were times when the kids would be with him and I could not focus on anything. The days seemed so long, yet so short. I would ask God why in a rage and cry until it hurt. Believe me, it does take time. In the beginning I had no hope for today as well as tomorrow. As time goes by my hope for my relationship with my husband faded and I hope for the future grew. It was about 3 months later that I could finally make it through a day without crying my eyes out. Today I am just angry for the affair and lies and the fact that I have to fight for custody of my kids against him and his girlfriend. But my life is great. I grew a lot for myself. I liked who I was again and began dating. I see nothing but good things for me in my future and you will too. Take care.

Try to remember one thing, you weren't the problem. My first husband cheated on me and now he is cheating on his current wife. That tells me he is the one with the problem. I know it hurts and nothing anyone does or says can really make the hurt go away.
One thing, You probably already know, is you are in greiving. There was a death. The death of a marriage. You need to mourn your loss in the way you feel you need to. You'll cry, you'll feel despair, which that I think you are doing now, then you feel anger and resentment and so on. What you are going through is very normal and we, who have all been there, feel for you and wish we could help more than words. Just keep letting your emotions out, it's better out than in.
Take it slow and pamper yourself a bit.

Easy does it Bro. It sounds like you're in the thick of it. For me, at this point of the Hell Sessions as I lovingly refer those days I found sharing the experience with others helpful. Try it. We're here for you.