Many believe your father deserves to know and that keeping the secret makes you an "accomplice" in the eyes of the law or family morality. Informing him may also relieve him of his own confusion if he already suspects something.
Full article: Exploring the lived experience of parental infidelity i caught my stepmom cheating
Talk to a trusted adult who isn’t directly involved — a school counselor, a relative you trust, a therapist. They can help you think through consequences without forcing you to take immediate action. Many believe your father deserves to know and
Days went by, and I couldn't shake off the feeling that something was amiss. I began to notice subtle changes in my stepmom's behavior – the way she would sneak out of the house for hours at a time, the way she would quickly change the subject when I asked her about her day. They can help you think through consequences without
Marcus froze. In that moment, the narrative of his family life fractured. The step-parent relationship is often delicate, built on years of negotiation, boundaries, and tentative trust. To catch a step-parent cheating is to realize that the stability you thought you had was built on a lie.
This leads to what we call 'triangulation.' The step-parent might try to befriend the child to keep the secret, or the child feels they must protect the biological parent from pain. It forces the child into an adult role—judge, jury, and executioner."