Recently my mom and step-dad haven’t been doing well relationship wise, which is pretty normal. People have their ups and downs. But my step-dad left two days ago to go on a cruise with my brothers for 8 days and on Saturday my mom planned a party. However I saw this one familiar guy there. And that guy and my mom hang out with each other very often. She’s always told me that they’re friends. But at night on Saturday when everyone left he was still here. I was in my room just on my phone when I hear two people heading upstairs which is pretty strange. Anyway I didn’t acknowledge it and just continued on looking through my social media’s, etc. but then I hear kissing and moans and that’s when I felt my heart drop down to my stomach. I’ve never felt so disgusted and just shocked. I balled my eyes out that night. I always had a feeling that something was up with the both of them. But seriously, they did it with the door open and everything as if they didn’t think I could hear them. I remember standing by my door silently crying. I felt frozen, I didn’t know what to do. To tell my dad or confront my mom, or to just keep it to myself. I chose the third option. The next night, Sunday night, I heard kissing again and I just felt so incredibly angry and disgusted. I knew I could NEVER get back on that bed without feeling nauseous. So fast forwarding to today I told my mom that I’m glad that we have the house to ourselves now and she got so mad at me. I seriously could not believe her. I know she can be insensitive sometimes but I just straight up could not believe her. And then she bring up the topic of how she doesn’t say anything when my friends are over but the thing is I don’t have sex with my friends nor do I do anything sexual with them. I honestly don’t know what to do anymore. I don’t want my younger brothers the be affected by this. Can anyone give me some advice?