Buddy, that is so difficult and so painful. I know the pain you talk about. I really can relate to how painful it is to experience love or care and how that feels like salt in the wounds. It hurts when we finally do feel love from others. For me, I think sometimes I have avoided letting care in because it was so painful.
What you are going through can feel like a death. I went through some stuff with my parents too, not the same situation as you, but what is the same is the inability to emotionally connect, and to be there. My parents did care about my kids, but they were still too caught up in their own defences to really be present with them, just like it was with me when I was growing up. They were there, but not there. In your case it's another step further, not even showing any interest. That hurts, deeply.
It's not your fault that this is the situation. It's not your fault your parents are incapable of showing love. It does not mean you aren't worthy of it. It's a deficit of theirs, not yours. I know it hurts anyway, though.
Not sure if you've heard of IFS (Internal Family Systems), but I've been reading about it for a few years now and finally started IFS therapy these past couple of months. It's already making a big difference to how I feel about myself. I just wanted to share this with you in case it's something that might be helpful for you as well. The IFS is really helping me start to feel more whole within myself, and more safe and worthy of care and love. It really becomes an internalized feeling and it's amazing. It doesn't take away the grief and the pain around our FOO, and we still have to go through the grieving process. But the IFS makes it possible to do the grieving.
I'm sorry you know all this pain too. You deserved better and your children deserve better too.
