I 12 years old, and I accidentally found out that my mother had been having an affair for a long time. I hate watching that man send messages to my mother every day. I want to remind my mother. ...

I think you'd better talk to your mother alone and tell her that you don't want her to make any more mistakes. Her behavior is harmful to you, your father and this family. You're sorry for her. Then you ask her what she thinks, whether to leave you and your father or not, and see how she answers you. If she doesn't want to leave you, she's just confused for a moment, then you tell her that if she can get rid of the man outside, you can keep this. I hope she can understand your pains.