If she is that kind of mother, she would have accused you of betraying her if you had not told her. She would have said you chose your father. Those kind of mothers you can't win with.
It isn't your fault they got a divorce. Don't say anything to your mom. There really isn't anything to say. She was in denial about problems in her marriage which might be one of the reasons your dad was cheating. She didn't face the problems in her marriage and she isn't facing them in the divorce. She blames others for her problems because she didn't work on them when they came to light. Just do what you need to do and when you get old enough, move out.
tell her to stop blaming you because she is the real reason behind...
she is in denial, dad did the cheating, wake up mum....
I think it was a mistake for you to tell her. After all, you could've blackmailed your dad with the information you had...<br />
Anyway, it is not fair for her to do that to you. Just ignore her.