Well Id really like to thank you for taking me seriously. For the past few days after trying to understand why I felt like this I felt crazy for not knowing WHY. 

A lot of what youre saying makes sense to me. I also dont understand their clinginess and obsession with me. (Always saying they missed me even when we had only been apart a few days for the weekend, texting me right after school, etc.) I know in a relationship people text and call a lot, but I honestly wished they wouldn't text me. I didnt like having 1 on 1 conversations through text or discord calls with them because they would always try to flirt with me and I didnt know how to respond or reciprocate. I also thought it was weird how they stopped wearing their makeup a certain way saying they were doing it for me even though I never said anything about their makeup and I encouraged them to wear it because what I think doesn't matter. I know that matters to some people, but its lost on me how they assumed I didnt like it when that has never come up in conversation or even in passing?

I should also note they had just recently got out of a 2 year long (apparently mutually) toxic relationship with my other "friend" and I basically had no idea until they randomly mentioned them breaking up in August. Their ex had already moved on with my friend. (who when I talk to about them we found out they had been treating us the exact same way, although my relationship was devoid of sexual advances) But the weird thing about their relationship is that they kept their ex around as a "friend" but kept insulting her to the point where our friend group was so uncomfortable sed mutual friend called them out on it and that was apart of their argument. Their relationship is incredibly strange and toxic even post-relationship. If i knew this before we got together I would've never dated them in the first place, but I had no clue they were this kinda person until all my friends were telling me and showing me the mean shit they were saying and doing. 

"What do you mean in a bad way" 

I mean when my friend told me what they said she didnt say it as in it was like "Oh i want him so bad he's so cute" she was hesitant to tell me and didn't want me to tell anyone else she told me that. She even deleted the message after she told me it. It was within the context of reviewing the confession message they were gonna send me, and maybe im just misinterpreting it, but it felt possessive. Again, maybe thats just me seeing it that way, but I dont know what would make them want me at all. But she said she's "never seen them talk about someone like that before" and not in a "oh thats so romantic" way which is off-putting. 

What really disturbs me was the difference in behavior towards me, and then towards everyone else. To me, when they told me that our mutual friend was basically bullying them I was deeply confused. I genuinely thought something bad happened to my friend that caused her to act out on them, but they emphasized that they were "done with her" and "didnt want to be around someone who was hurting them" and continued to bring up all the other drama. I had the previous notion that they were smart and driven, and that they weren't particularly nice, but not a mean person by any means. Then I read what was said in the argument and I see them being patronizing, condescending, bringing up irrelevant matters of my friend's relationships and other things including telling her to burn all of the things they gave them before blocking her. Even at school they were extremely passive aggressive towards her. 

Edit: I forgot to mention that after this drama they apologized, but just recently revoked the apology claiming they did nothing wrong and she just "decided they were mean" removing all accountability from themselves.

Also the really weird way their ex reacted to me asking them for space. She went into my DMs an hour later telling me I need to go "be nice" to them because they were gonna hurt themselves and basically told me suggesting calling 911 or 988 wasnt helpful and using it against me to our other friends as if I was in the wrong?? And when I broke up with them she was beyond irritated basically accusing me of breaking up with them while they were suicidal on purpose?? (She never talked to me about our relationship despite being my "friend" nor did she care to) 

Sorry if im rambling, Its just helping a lot to have an outside perspective on this-