I accidentally saw an ambiguous message with another woman on my father's mobile phone, but I was afraid that my mother would get sick or even divorce. What should I do?

If you think you have the ability to communicate well with your father, ask your father. Don't tell your mother yet Maybe your mother knows, but she just doesn't want to tell anyone, or your mother has someone outside and just plays with each other. If your father is an asshole and your mother is an honest person, you can tell your mother and keep the evidence. If you divorce, you can get more property according to the evidence.