6 years of wasted energy

This is my first post on this blog. I am newly separated from the N in my life. He was my husband for 3 years and we have been together so 6... I have read Lisa's book and have covered all steps. The most difficult one I am having trouble with is the No Contact. I go a few days alright but by the 4th or 5th I almost need it, like an addiction.
I have also recently been advised that he has been having an affair and had one early in our relationship as well. But I just can't seem to get passed it. I know he does nothing good for me or our daughter but it is just soo hard...
And I should know better bc after every conversation we have I feel worse and worse about my self. It is MY fault that our relationship disintergrated, it is MY fault... MY MY MY... It is so heartbreaking. To have given myself, heart and soul and to now have to start over.. it is scary as hell!!!!!!!!!!!!
I have read other ppls post and I can completely relate but I just need some pointers on how/what I can do that will help me get through these tough times..