I am so much more healed than I thought I was, it was just her avoidance messing with me
For context, we were together for two and a half years. The first six months were good (mirroring phase) but there were some red flags I ignored, mostly the fact that she wouldn't share feelings or thought processes with me and that she always seemed a bit weird in romantic moments. But everything else was too good so I wasn't too worried about those things and even thought they would improve with more time.
After those six months, she turned into a completely different person. All forms of affection stopped, I had to ask her repeatedly to make room for me in her life (which always made her angry), she showed me that she was completely unwilling to compromise on anything, and she would criticize me constantly for different and often contradictory things. Oh, and she also confessed to me over time that she actually hated all the things we did during the good period (which did great things to my confidence, as I'm sure you can imagine. There's nothing like being told that your partner didn't like the version of you that wasn't trying to please her).
I spent the two bad years trying to change myself into the kind of person who would make her return to the version of her I fell in love with at the beginning. Yes, I was anxious early on, but I threw myself into learning everything I could about anxious attachment the second we got together, and I eventually stopped asking for reassurance.
I now believe that the more subtle way my anxious attachment kept showing up was that I stayed for as long as I did. The version she became later in the relationship is someone I wouldn't even want to be casual friends with. The one good thing that came out of it was that I grieved the relationship while still being in it, and I came out of it angry at how someone could treat another person like this, but otherwise pretty indifferent. It's less like I'm going through heartbreak, and more like someone I was close to died, and after that I was with someone I didn't really like for two years. Those two things don't feel connected and it doesn't feel like they were ever the same person.
Here are some things I've learned: The big reason I was drawn to her was that she had something that I lacked as a result of my anxious attachment at the beginning of the relationship, the fact that she was able to meet her own needs and be unapologetically herself. I was neglected and bullied growing up, and learned that I had to work for love and that people didn't like my true self. In truth, I think a lot of her "true self" is things I actually wanted to do as well, but felt like I wasn't allowed to. I was looking for someone else to give me permission to be myself by accepting me. Unfortunately this led to me only feeling like I was "allowed" to do things she agreed with, which is part of why I essentially turned into a slave trying to please her.
I am so, so much more confident now that she's no longer in my life. I feel much more capable and have so much more time for hobbies because I'm not spending all of my energy trying to please her. But obviously the core wound that caused me to enter into this relationship hasn't just disappeared, and that is something I'm actively working on. A major belief I'm in the process of unlearning is that I only "deserve" to be myself with a select few people once they've shown me that they accept me. That feeling was part of why I stayed; I felt like I had no other choice, because breaking up would mean losing that part of myself. I deserve to be my true self with everyone I meet, and if people don't like me, there are others out there who will (getting rid of the acceptance scarcity mindset is a huge part of healing, I think).
I also asked myself why it's so hard for me to do things for myself. I discovered that it's because I never got the external validation that who I am and what I want to do is okay, and I feel bad prioritizing myself for the same reason, i.e., I am clearly not someone who should be prioritized and it would be embarrassing if others saw me prioritizing myself. To work on this, I am constantly reminding myself that I do deserve to do things, and growing friendships with as many people as possible to actively show my brain that people don't actually hate me. This helps with both the "prioritizing myself is embarrassing" and the "I can only be myself with a select few people" problem. If you're in the process of healing, ask yourself if you have similar beliefs about whether you "deserve" to be yourself and have agency. It's been super helpful for me.
Also, if you feel free to be yourself, you will eventually find the sort of relationship you actually want! You can be confident about your wants and needs, and it won't destroy you if one person doesn't want to be with you because you will have a network of people who accept you to fall back on <3