Losing trust with your spouse?

okay this is going to be involved. i met my wife, we married. she had a child with according to her was a psychopath. hit her, beat her, cheated on her. okay but then she wanted to study abroad. i let her. the child's father moved to where she was. tracked her down. we had agreed that the man should not be in that child's life because of the emotional damage he could do given what she said he was. today i find out that she not only let that man see that child but left the child with him. i went ballistic. we had an agreement. i know that a child's emtional development is important. he called me dad now he calls that man daddy. she thinks she did nothing wrong. i'm thinking about calling it quiets. not only did she do that but the big thing is we had an agreement and that man hasn't been in his life for 3 years now he has changed apparently and i'm done. what would you do?