I think what you're feeling is part of the grief process. You go through stages, anger, denial, depression, etc. So what you're feeling is understandable. I've been separated 20 months now, going through divorce proceedings. My ex has moved on and has started a life with a new woman. I have a loving, caring, romantic boyfriend. But, even now, 20months on, I still feel a responsibility toward my ex. I worry about his health, I worry that he's not happy with his partner, that she's manipulative. My ex is totally horrible toward me and our children and he's set to make me suffer financially and emotionally in the divorce - and yet two days ago I wished he were back home and I regretted that I ever let him leave. And this is a man that was a binge drinker our entire marriage. I think it takes a long time to detach from a person and I wonder sometimes if people ever do completely. I guess what I'm saying is, it takes time. I still have my emotional days after 20months. I cry when I think about nice things that happened during the marriage.
And you're right, being with someone so long and from such a young age, your identity and who you are does become linked with them. But as time goes on you'll find who you were before. You'll listen to music you listened to before him and dress how you want, eat what you want and do what you want. What I've learnt from this whole process is getting to know someone and trusting them can take a long time and it's a risk. But it can be worth it with the right person.
I've been looking for someone to relate to and your post hit home for me. It's been 4 years since my separation and I feel exactly the same as you've described. Still feeling like he'll come around. Not back to me but hope for his depression to lift. For him to appreciate and live the life that's in front of him.
As for moving on, I personally believe and I have most of my life that men are not going to work out for me. They are so damaged and self-absorbed as you said, that there is no way I could ever be myself and not feel repressed. I could never feel as happy as I do now. The freedom I feel now and being who I am 100% without ever apologizing for it. Tip towing around someone who is so insecure is not a way for me. In the end my ex did me a huge favor with the ultimate betrayal.
I've never had an explanation as to what happened. Which only justifies the pack of respect and the understanding that he never loved me which brings me to a closure all on its own.
So for you it's time that heals and rediscovering what you really want and who you are independent of others.