My siblings are having sex

Now as much as this embarrasses me to reveal to you its only for the good of my family. First a backstory: my mom divorced my dad when I was 3, leaving me and my brother Ian with mom. My dad disappeared so my mom didnt fear marrying again. She married my new dad four years ago. I got a sister Micah and two brothers Ben & Ty. Well focus on Ian & Micah. Since the day my mom remarried they're enemies. Ian started the tyranny over Micah & then they both were reckless. Ian wasnt afraid to be violent towards her. He also cusses her out. Micah just yells & screams at Ian and can sometimes throw a kick.

It happened a long time ago so I have a not as good memory. It was the day before Halloween. My parents were out with Ben and Tyler taking them to a friends house to sleep over. Since it was a long drive, I sticked home with Ian and Micah talking to my friend on the cell. I could still hear them arguing over stuff from his room to her's. Ian would go back and back to her door and kept knocking on it in madness. Micah never came out. Around eight, my parents were not home still and the shower had turned on. My problem was that I needed to get the keys to my brother's car to drop something off at my friend's house down a few blocks that was necessary. He never minded me driving it but the keys were in Ians room. Anytime he's in his room, the door is locked, which I had learned to picked. I was afraid to go in though in case he was pissed. But my friend really needed this thing so I took the risk. I picked Ian's lock and opened the door quietly to see in his room. Nobody on his bed, I figured he was showering. So I walked casually in but made a quick look on both sides. I looked left than right.

Once I had looked right, I saw the bathroom. In front of me was the shower with its curtains open. Ian and Micah completely naked were tackling each other against the wall of the shower, kissing and feeling each other slowly. In shock my legs gave out and I fell to the floor. I lost breathe and began to get stomach cramps in shock. I don't know what was happenning and why but I ran out without thinking, slammed the door. I didn't get signals for quite a while that either of them knew i saw.

Then I began getting weird emotions from both Ian & Micah. Both acted the same way at them selves but treated me different. Ian was letting me into his life, treating me like a best friend. It worried me & he talked to me about what was going on & that he knew what I saw. He used nice words & a light voice. Micah kept coming onto me like a best friend. Ok at first until she began wearing small clothes & sitting on me & stuff. Once we were watching a movie at home with the family, me and Tyler were the only ones still awake. Micah had her head on my shoulder. Her hand was on my leg inching towards my crotch. I ignored it til her full hand was on my penis. I ran & she saw, & giggled. So Im not sure. Did Micah see me see the shower hap or did Ian tell her?

Help?