My first proper relationship, she turned out to be a horrendously awful emotional abuser, but it took me a year being with her to truly figure out why I was so miserable. E.g.:
- Constant random cold shoulder treatment when I did nothing wrong, then suddenly acting all affectionate again pretending like nothing happened, leaving me wondering what the hell was going on and questioning myself, slowly wearing me down over time. This happened constantly and nearly drove me literally insane, got me very depressed and persistently anxious about her feelings towards me.
- Deliberately did things to make me jealous then turning it back onto me if I ever reacted to her 'deeds', making out like I'm being irrational. I later caught her out lying to me on multiple occasions about multiple guys.
- Always trying to put a divide between me and my group of friends (including my brother) when it wasn't necessary, always telling me they treated her badly when I knew for a fact they weren't and would attack me whenever I tried to reassure her. I made a genuine effort to make her as comfortable as possible at all times, in the end it just seemed like she enjoyed the attention from everyone being extra nice to her and just came to expect it all the time.
- Hid our relationship. Before we got properly together she was going on dates with somebody else besides me (exploiting his feelings towards her for car help), meanwhile telling me the whole time she wasn't interested in him. I'm not stupid though, and clearly I could see something was still going on. That was later confirmed once we got together when she asked me to not say anything if the guy started asking me about us... that completely threw any trust for her out the window. It also didn't help she kept sneakily chatting to him and other guys for months afterwards, until the guys themselves got bored with her.
- Always twisted the knife on my guilt to its fullest extent every time I made any little mistake such as confusing future plans, and never passing up the chance to punish me as much as possible without mercy, even after realising to herself that she was overreacting. God forbid I would ever call her out on a mistake
, she always made me feel like she didn't need me and would just break up with me if I had a got angry at her about anything.
- And countless other things which would get me typing here forever...

From all of this I was pushed to the point where I felt like it was all my fault and she wasn't to blame in any of it. By her own manipulation she engineered the relationship to the point where I was always on the backfoot regardless of everything I did for her, and she would always be the one calling the shots.
One day she found out I was talking about our relationship problems with my family, she completely flipped out and played the guilt card the hardest way ever, acting like I betrayed her trust etc etc, not once attempting to understand what drove me to it in the first place. I decided right then, enough was enough and walked out.
Took a while to figure out what sort of relationship it was, but looking back it's so clear now, should have listened to my family & friends rather than trying to defend her whilst blaming myself.
I later discovered she treated her previous boyfriend exactly the same way.
So glad to be out of that relationship, and learned a lot