When I was 10 my parents got divorced. It was messy. There was domestic violence. The whole package of childhood nightmares. During that time he brought a women to live with us (my mom moved out). He had sex with her in front of us. I witnessed him doing inappropriate things to her in the kitchen while we were eating breakfast multiple times. Right in front of us.
During that time I also sexually abused my little sister. I was 10. She was 6. We played 'husband and wife'. There was dry humping and groping over clothes. There may have been one kiss. No penetration or skin-to-skin contact, though I did expose myself to her once for a few seconds. It happened 3, maybe 4 times over a few weeks. There was no coercion, threatening, or bribery. It felt playful and naughty at the time. Dad found out and didn't say much but he did tell his girlfriend who completely demonized me. She said I was a monster and that my little sister would be coming to live with her to 'get her away from me'. I had never felt so low in my life. We talked to a psychologist and my little sister said she didn't remember anything, but I told the doctor what happened and she said not to let it happen again. We moved out of my dad's house and in with my mom shortly after for unrelated reasons.
We never mentioned it again. Fast forward a few years (I'm now 19, she's 15) and she supposedly told my mom she feels guilty and 'dirty' about it and it contributes to her food addiction. I had hoped she'd forgotten. My stomach sank. All these years the guilt I've felt, the shame, they've never lessened. I've talked to a couple therapists over the years for anxiety and we've talked about the incident and they've all said I was a victim of sexual abuse too. A damaged child damaging a child- an inappropriate event born out of an unhealthy home. Something I wouldn't have done otherwise.
But that doesn't make me feel any better. I did it. I was older. She was my little sister. I should have protected and sheltered her. Instead I feel like I defiled her. I feel like a monster and a predator. Who I was then, the things I did, and who I am now are so far apart it feels like a different life but I can't erase the things I did.
So, was what happened sexual abuse? experimentation? And regardless, it's clearly a sore spot. Should I talk to her about it? How? Or wait for her to come to me? I just want her to know how sorry I am and how I haven't forgotten and won't brush it under the rug or undermine her pain. I love her so much. I just want us to have a healthy brother-sister relationship.
I'd really appreciate opinions, advice, or wisdom anyone has to offer.