Kept being SA'd as a secret from myself TWICE

I (M19) posted for the first time on here yesterday and I realised it's a good way to get this off my chest anonymously

My current friend group consists of my older brother, my girlfriend and technically my only friend.

I recently remembered that when I was 9-10 and my older brother was 14-15 he 'experimented' with me (sexually) and obviously I didn't understand any of it but I did it, and he told me not to tell our parents.

I scarecly remember anything from before my teenage years. I've realised that I haven't thought of even remembered this experience until about a year ago but I feel like it's effected a lot of my life I hit puberty at 11 I gave pictures of my body to creepy guys on the Internet while I was 15 And I lost my virginity at 14

A bunch of bad sexual things have happened to me and I didn't know it was because I was fighting a battle I didn't even remember. I got my first girlfriend when I was 15 and she introduced me to her friend, him and everyone else I knew kept telling me my gf was toxic. Her friend ended up becoming more my friend than hers, but eventually he ended up touching me in front of her, he sent me nudes without me asking or wanting them, I was loyal to my gf. But to be honest I encouraged him after a while, because I felt like I deserved ig because my gf was toxic, but I hated it, I don't know why I did this. I got a grip and cut ties with him, and developed a fear of cheating l, regretting what I had done, but my gf resented me for it, I couldn't tell her that I didnt want it because I encouraged the guy eventually. She broke up with me a year after saying it was because of that but turns out she was cheating on me.

I started having sex with a lot of people, possibly to get over it, but at that point I think I felt that it's all I was good for.

Moving to college I got a bf, he made me have sex with him a lot, like a lot (he was mingin) and he ended up just being a horrible person, he stabbed me but that's a different story.

But all of this I feel came from my older brother experimenting with me when I was a kid. I can't tell anyone about it, one third of the people I'm friends with is the older brother, and the others are friends with him, he's not like this anymore and I don't want my friends to think he is. I have a good sex life and relationship with my gf now and I've told her about my trauma with my ex bf and the guy but I can't tell her why I think it happened to me specifically.

I also feel I had a slight porn addiction because of this but I didn't want this to taint my idea of sex anymore or to effect my relationship with my gf so I went cold turkey and have recently got over it.