<human>: Can you provide a brief rundown of the text in within 3 sentences?

Yesterday I came home a little earlier than usual and heard noises from my parents bedroom. I knew my mother was working at that time so I was shocked. I went back out and looked at our house from a distance. About half an hour later a man left our house. I went in at the time I was supposed to and my dad was acting totally like normal.

I'm now incredibly confused. My parents always seemed like a perfect couple and the idea of my dad cheating on her grosses me out completely. I can't imagine my dad is like that and I feel horrible for my mom.

I don't know what to do. I thought that if I tell my mom it will cause a divorce and I don't want that to happen. I thought at first that I'll tell my dad and make him promise me to stop it but doesn't my mom deserve to know? I don't know. I'm confused. What should I do?
<bot>: Came home to find my dad having sex with a man. I feel horrible and shocked and now I don't know if I should tell my mom or not as it may cause a divorce.