Complicated Friendship Advice.

[Mist_T123]

My best friend recently moved in with a new family relatively close by and I visit him every once in while (2-4 times to sleep over a month). He got a new sister sort of who isn't related by law or blood and he ended up to the point where he at least thought he loved her (we're 14-15). Every once in awhile he would do inappropriate things like touching the inside of her mouth and keeping his fingers there (he did say he felt bad) ect. for like 4-5 times. Meanwhile during all this time I'm trying to get trough to him to stop and comfort her at the same time (imagine as little touching as possible bc I'm really awkward around women right now as a only child guy with no nearby friends). So time flies things get better but emotions I had been trying to get rid of needed to be said because I accidently pretend choked the girl when she had already said that was one of her kinks (I forgot :( ). So I got guilty and felt that she deserved to know at that point that I did had those kinds of feelings for her but to not worry about it because I would never act on my emotions like that and I knew hat she didn't feel the same way. Soon after I go home and she almost ghosts me compared to when we had talked everyday for hours and this goes on a month. She doesn't talk and I don't sleep over. This really hurt because I literally only have the two of them as what I'd call friends in my life and hit extra hard because I'm already an only child with no one nearby and parents who I'd rather avoid talking to if I can help it. During that month it's always me that engages in the talks that always seemed to end in 7 or less short messages. Month ends, I see her, ask her about it and she says she was try to give me space to think and then didn't know how to approach/talk to me anymore. But to my surprise her and my best friend are hitting it off better than ever. Suddenly while they're sharing a pillow I'm constantly out of the loop because they talk so low (during movies). My best friend has these sad moments but I feel like sometimes he fakes them spontaneously to get her to focus more on him (really out of place moments). This seriously annoys me because I'm trying to at least get back to how things were with us after all of my abandonment trauma (more so caused by my past experiences and why I don't have many friends). A previous day he walks out and we both ask what's up and try to comfort him. Same for the girl. Almost immediately. Next day I go outside to think/test them and only the girl comes out after like 10 minutes to ask what's up. Now I have to worry about my best friend not caring about me anymore. So later in the night I texted him I was hurting about being feeling like I was being ignored by the two of them. No response on that. Slightly better the last time I saw them but only because of like 1-2 quick laughs they shared with me. What do you think I should be thinking right now? Anything I should do when I see either or both again?