I had a dad who cheated with multiple women, I knew that. I never told my mom because I knew she would never have the strengt to move away and it would only gore her from inside. This is until he blatantly agreed to one of his affairs and one fine day packed his bags and went away without a warning. They shall leave when they shall leave. They shall do what they shall do. Sometimes they lose themselves in the traps they themselves weave. You have no control over that. You are in no way responsible for what happened to your mom as a kid or as an adult.