Why am I being punished for her affair?

This is our second marriage for both of us. In our mid 40's and with a 4 year child, my wife has a cyber affair that is pretty involved to the point of sending photos, small amounts of money to one of them because he was poor and so forth. I couldn't get an honest reply for all the pleading I did to come clean on this and talk things out so when I found she was planning (I implanted webwatcher and got 2 weeks of chat and emails to find out the real story) to leave with our child when I worked out of town, I filed for custody to get her attention and protect my child from these freaks. 5 months go by and she talks me into dropping it and go to counseling, after 5 times she said its not helping us and stops...she gets a job in a daycare enrolls our girl then files for divorce and wins custody because I'm not a nuturing parent in the court's eyes due to my working out of town making it so she could be an at home mother initially..she got the job after she filed. So why am I being punished by losing my child and her coming out on top financially with me paying her over 800 a month in support and she still blames me for her cheating. I do feel as though she really did cheat....even though it was not physical to my knowledge as he was states away. The emotional detachment and commitment left me cold and empty for her......I never shed a tear and yet I have so much resentment and hate it consumes my being. My only child and I truly feel as though I tried my best in it all, even if I did fail on some levels. I don't want her back and she is despicable in my eyes. I want nothing from her for what she has done, but for me to see her feel some kind of loss......she is now on her 4th person dating locally with custody of my child inside of a year....WTF is wrong with her, I can't do a thing to protect my child from these potential wierdos. I don't care what she does, but around my little girl.......I just want to kill her and protect my child is how I am feeling, its really bothering me. How do I cope.......please tell me how I can cope? Cut and paste (blackriverrt3@gmail.com) if you sincerely can help me past this, I have no one I can sincerely confide in...its been going on too long, I can't take these feeling much longer.