Turning 27 soon and no relationship… what is wrong with me?

I am feeling really awful about my past experiences and attitudes to dating. I have been completely closed off, turning down any signs of interest from others for years now, since I was 21, all because the first massive rupture with the guy I wanted to spend my life with, that just became an abusive charade for him, with me being an emotional mess, and him not committing to me, despite saying he loved me. Now he's in a relationship, he's found his person, he got off scot free. Yes he did text, but that's okay, he just wants control over me. I gave him that control and I lost myself. I feel so unlucky. I didn't get those happy memories of a young relationship, all he gave me was grief and that's because I felt I deserved it due to my upbringing, and what felt familiar to me was all the chaos and instability. I can see that now.

I've been struggling for years to deal with trust issues he and others have given me, and so resorted to shutting myself off from others. I definitely have some kind of attachment issue based on bad upbringing, I wish I had been able to get over him and believe in love, but I could never again. My parent's relationship made me see love as a terrible, painful thing.

When I see others in couples around me I just feel pain. I hate myself because it feels like I'm this jealous, bitter person inside me (I don't show it or say anything but it's there). I also hate that I'm self-pitying about not getting that relationship… but it feels so desperately unfair. I look at myself and think what is wrong with me. Others say there is nothing wrong with me and give me compliments about being attractive but the way men have treated me I really don't feel it deep within. I just feel like there's something badly wrong, like I'll never be enough.
I am going through therapy and have done self work but my fear is that I am running out of time. I don't know why I have let these years slip by. I feel like there is something desperately wrong with me, and it's all hitting home now.

I am feeling these issues more so now because of the covid and the loneliness of living alone. I wish I had a partner here. Everyone around me has either been in some long term relationship since they were young, or found their person and got engaged/settled down.

Soon I'm turning 27 and I won't be anyone's first love, or the person they want to spend the rest of their life with. If I get anything out of life I'll be someone's second choice and basically settle at this point.