Suffering as if it was day one.

I am three years into trying to cope with this affair and there are so many times where I feel like it was day one. I always hear the saying and have said it myself that "it gets better with time." I now strongly disagree with that statement.
I have become more sensitive to everything. My self esteem is the lowest that it has ever been. I am so tired of having to be strong and work on doing what is right by everyone else but feel like no one is doing what is right by me. I am no longer me and I don't know how to get that back. Yes, I have done the counseling, the meditation, mindfulness, positive self talk, support groups, talk with friends, read books, etc. You name it, I have done it and still feel like SHIT. I am holding on by an extremely small thread and that is only because of my children. Unfortunately, I do not have the strength to pull myself out to put on a better front for them anymore and they see it.
 
Little things that I did not let bother me now tear me a part and I just spiral down. I never thought I would ever let anything in life get me to this place in my life. I always prided myself being able to handle anything.
 
I was thinking the other day as to why this is hurting so much and I realized that not only did I not have a loyal husband but also that he was not really my best friend as I had believed. I am suffering a lot because the one person I would talk to about what was troubling me was the one who hurt me the most.
 
I am not sure why but recently I have been struggling everyday to get through the day. In the past it was usually a few bad days and a few good days but now everyday is bad. I am actually scared because I have NEVER felt this way and it is only getting worst.